diff --git a/include/wx/gtk/private.h b/include/wx/gtk/private.h
index cd78c537c2..dbbaa21d54 100644
--- a/include/wx/gtk/private.h
+++ b/include/wx/gtk/private.h
@@ -30,16 +30,6 @@
 // and use it only to test for pango versions >= 1.16.0
 extern const gchar *wx_pango_version_check(int major, int minor, int micro);
 
-#define wxGTK_CONV(s) (s).utf8_str()
-#define wxGTK_CONV_ENC(s, enc) wxGTK_CONV((s))
-#define wxGTK_CONV_FONT(s, font) wxGTK_CONV((s))
-#define wxGTK_CONV_SYS(s) wxGTK_CONV((s))
-
-#define wxGTK_CONV_BACK(s) wxString::FromUTF8Unchecked(s)
-#define wxGTK_CONV_BACK_ENC(s, enc) wxGTK_CONV_BACK(s)
-#define wxGTK_CONV_BACK_FONT(s, font) wxGTK_CONV_BACK(s)
-#define wxGTK_CONV_BACK_SYS(s) wxGTK_CONV_BACK(s)
-
 // Define a macro for converting wxString to char* in appropriate encoding for
 // the file names.
 #ifdef G_OS_WIN32
diff --git a/include/wx/x11/private.h b/include/wx/x11/private.h
index ce09cc4ae5..f0912b1eca 100644
--- a/include/wx/x11/private.h
+++ b/include/wx/x11/private.h
@@ -35,13 +35,6 @@ class WXDLLIMPEXP_FWD_CORE wxMouseEvent;
 class WXDLLIMPEXP_FWD_CORE wxKeyEvent;
 class WXDLLIMPEXP_FWD_CORE wxWindow;
 
-// ----------------------------------------------------------------------------
-// Some Unicode <-> UTF8 macros stolen from GTK
-// ----------------------------------------------------------------------------
-
-#define wxGTK_CONV(s) wxConvUTF8.cWX2MB(s)
-#define wxGTK_CONV_BACK(s) wxConvUTF8.cMB2WX(s)
-
 // ----------------------------------------------------------------------------
 // we maintain a hash table which contains the mapping from Widget to wxWindow
 // corresponding to the window for this widget
diff --git a/src/generic/statusbr.cpp b/src/generic/statusbr.cpp
index adbc7d498b..9c571d3cb0 100644
--- a/src/generic/statusbr.cpp
+++ b/src/generic/statusbr.cpp
@@ -71,7 +71,7 @@ gboolean statusbar_query_tooltip(GtkWidget*   WXUNUSED(widget),
     if (str.empty())
         return FALSE;
 
-    gtk_tooltip_set_text(tooltip, wxGTK_CONV_SYS(str));
+    gtk_tooltip_set_text(tooltip, str.utf8_str());
     return TRUE;
 }
 }
diff --git a/src/gtk/aboutdlg.cpp b/src/gtk/aboutdlg.cpp
index 95fe64780e..04abafeb4b 100644
--- a/src/gtk/aboutdlg.cpp
+++ b/src/gtk/aboutdlg.cpp
@@ -57,7 +57,7 @@ public:
             // existence the pointer persists in wxString which uses it either
             // for internal representation (in wxUSE_UNICODE_UTF8 case) or as
             // cached m_convertedToChar (in wxUSE_UNICODE_WCHAR case)
-            m_strings[n] = wxGTK_CONV_SYS(a[n]);
+            m_strings[n] = a[n].utf8_str();
         }
 
         // array must be null-terminated
@@ -102,7 +102,7 @@ static gboolean activate_link(GtkAboutDialog*, const char* link, void* dontIgnor
 {
     if (dontIgnore)
     {
-        wxLaunchDefaultBrowser(wxGTK_CONV_BACK_SYS(link));
+        wxLaunchDefaultBrowser(wxString::FromUTF8(link));
         return true;
     }
     return false;
@@ -112,7 +112,7 @@ static gboolean activate_link(GtkAboutDialog*, const char* link, void* dontIgnor
 extern "C" {
 static void wxGtkAboutDialogOnLink(GtkAboutDialog*, const char* link, void*)
 {
-    wxLaunchDefaultBrowser(wxGTK_CONV_BACK_SYS(link));
+    wxLaunchDefaultBrowser(wxString::FromUTF8(link));
 }
 }
 #endif
@@ -124,21 +124,21 @@ void wxAboutBox(const wxAboutDialogInfo& info, wxWindow* parent)
         gs_aboutDialog = GTK_ABOUT_DIALOG(gtk_about_dialog_new());
 
     GtkAboutDialog * const dlg = gs_aboutDialog;
-    gtk_about_dialog_set_program_name(dlg, wxGTK_CONV_SYS(info.GetName()));
+    gtk_about_dialog_set_program_name(dlg, info.GetName().utf8_str());
     if ( info.HasVersion() )
-        gtk_about_dialog_set_version(dlg, wxGTK_CONV_SYS(info.GetVersion()));
+        gtk_about_dialog_set_version(dlg, info.GetVersion().utf8_str());
     else
         gtk_about_dialog_set_version(dlg, nullptr);
     if ( info.HasCopyright() )
-        gtk_about_dialog_set_copyright(dlg, wxGTK_CONV_SYS(info.GetCopyrightToDisplay()));
+        gtk_about_dialog_set_copyright(dlg, info.GetCopyrightToDisplay().utf8_str());
     else
         gtk_about_dialog_set_copyright(dlg, nullptr);
     if ( info.HasDescription() )
-        gtk_about_dialog_set_comments(dlg, wxGTK_CONV_SYS(info.GetDescription()));
+        gtk_about_dialog_set_comments(dlg, info.GetDescription().utf8_str());
     else
         gtk_about_dialog_set_comments(dlg, nullptr);
     if ( info.HasLicence() )
-        gtk_about_dialog_set_license(dlg, wxGTK_CONV_SYS(info.GetLicence()));
+        gtk_about_dialog_set_license(dlg, info.GetLicence().utf8_str());
     else
         gtk_about_dialog_set_license(dlg, nullptr);
 
@@ -157,11 +157,11 @@ void wxAboutBox(const wxAboutDialogInfo& info, wxWindow* parent)
         gtk_about_dialog_set_url_hook(wxGtkAboutDialogOnLink, nullptr, nullptr);
 #endif
 
-        gtk_about_dialog_set_website(dlg, wxGTK_CONV_SYS(info.GetWebSiteURL()));
+        gtk_about_dialog_set_website(dlg, info.GetWebSiteURL().utf8_str());
         gtk_about_dialog_set_website_label
         (
             dlg,
-            wxGTK_CONV_SYS(info.GetWebSiteDescription())
+            info.GetWebSiteDescription().utf8_str()
         );
     }
     else
@@ -214,7 +214,7 @@ void wxAboutBox(const wxAboutDialogInfo& info, wxWindow* parent)
     }
 
     if ( !transCredits.empty() )
-        gtk_about_dialog_set_translator_credits(dlg, wxGTK_CONV_SYS(transCredits));
+        gtk_about_dialog_set_translator_credits(dlg, transCredits.utf8_str());
     else
         gtk_about_dialog_set_translator_credits(dlg, nullptr);
 
diff --git a/src/gtk/bmpcbox.cpp b/src/gtk/bmpcbox.cpp
index d355d4a96a..62b9f0db17 100644
--- a/src/gtk/bmpcbox.cpp
+++ b/src/gtk/bmpcbox.cpp
@@ -295,7 +295,7 @@ void wxBitmapComboBox::GTKInsertComboBoxTextItem( unsigned int n, const wxString
     gtk_list_store_insert( store, &iter, n );
 
     wxGtkValue value( G_TYPE_STRING );
-    g_value_set_string( value, wxGTK_CONV( text ) );
+    g_value_set_string( value, text.utf8_str() );
     gtk_list_store_set_value( store, &iter, m_stringCellIndex, value );
 }
 
diff --git a/src/gtk/button.cpp b/src/gtk/button.cpp
index a52f9cbd6f..846f257737 100644
--- a/src/gtk/button.cpp
+++ b/src/gtk/button.cpp
@@ -268,7 +268,7 @@ void wxButton::SetLabel( const wxString &lbl )
     // so "use-underline" GtkButton property remained unset
     gtk_button_set_use_underline(GTK_BUTTON(m_widget), TRUE);
     const wxString labelGTK = GTKConvertMnemonics(label);
-    gtk_button_set_label(GTK_BUTTON(m_widget), wxGTK_CONV(labelGTK));
+    gtk_button_set_label(GTK_BUTTON(m_widget), labelGTK.utf8_str());
 #ifndef __WXGTK4__
     wxGCC_WARNING_SUPPRESS(deprecated-declarations)
     gtk_button_set_use_stock(GTK_BUTTON(m_widget), FALSE);
diff --git a/src/gtk/choice.cpp b/src/gtk/choice.cpp
index c91acbafb0..2d57459f8b 100644
--- a/src/gtk/choice.cpp
+++ b/src/gtk/choice.cpp
@@ -142,9 +142,9 @@ bool wxChoice::GTKHandleFocusOut()
 void wxChoice::GTKInsertComboBoxTextItem( unsigned int n, const wxString& text )
 {
 #ifdef __WXGTK3__
-    gtk_combo_box_text_insert_text(GTK_COMBO_BOX_TEXT(m_widget), n, wxGTK_CONV(text));
+    gtk_combo_box_text_insert_text(GTK_COMBO_BOX_TEXT(m_widget), n, text.utf8_str());
 #else
-    gtk_combo_box_insert_text( GTK_COMBO_BOX( m_widget ), n, wxGTK_CONV( text ) );
+    gtk_combo_box_insert_text( GTK_COMBO_BOX( m_widget ), n,  text.utf8_str() );
 #endif
 }
 
@@ -248,7 +248,7 @@ int wxChoice::FindString( const wxString &item, bool bCase ) const
     {
         wxGtkValue value;
         gtk_tree_model_get_value( model, &iter, m_stringCellIndex, value );
-        wxString str = wxGTK_CONV_BACK( g_value_get_string( value ) );
+        wxString str = wxString::FromUTF8Unchecked( g_value_get_string( value ) );
 
         if (item.IsSameAs( str, bCase ) )
             return count;
@@ -277,7 +277,7 @@ void wxChoice::SetString(unsigned int n, const wxString &text)
     if (gtk_tree_model_iter_nth_child (model, &iter, nullptr, n))
     {
         wxGtkValue value(G_TYPE_STRING);
-        g_value_set_string( value, wxGTK_CONV( text ) );
+        g_value_set_string( value, text.utf8_str() );
         gtk_list_store_set_value( GTK_LIST_STORE(model), &iter, m_stringCellIndex, value );
     }
 
@@ -299,7 +299,7 @@ wxString wxChoice::GetString(unsigned int n) const
 
     wxGtkValue value;
     gtk_tree_model_get_value( model, &iter, m_stringCellIndex, value );
-    return wxGTK_CONV_BACK( g_value_get_string( value ) );
+    return wxString::FromUTF8Unchecked( g_value_get_string( value ) );
 }
 
 unsigned int wxChoice::GetCount() const
diff --git a/src/gtk/collpane.cpp b/src/gtk/collpane.cpp
index ae98507af7..b88a042cff 100644
--- a/src/gtk/collpane.cpp
+++ b/src/gtk/collpane.cpp
@@ -145,7 +145,7 @@ bool wxCollapsiblePane::Create(wxWindow *parent,
     }
 
     m_widget =
-        gtk_expander_new_with_mnemonic(wxGTK_CONV(GTKConvertMnemonics(label)));
+        gtk_expander_new_with_mnemonic(GTKConvertMnemonics(label).utf8_str());
     g_object_ref(m_widget);
 
     // Connect to the "notify::expanded" signal instead of the more common
@@ -209,7 +209,7 @@ bool wxCollapsiblePane::IsCollapsed() const
 void wxCollapsiblePane::SetLabel(const wxString &str)
 {
     gtk_expander_set_label(GTK_EXPANDER(m_widget),
-                           wxGTK_CONV(GTKConvertMnemonics(str)));
+                           GTKConvertMnemonics(str).utf8_str());
 
     // FIXME: we need to update our collapsed width in some way but using GetBestSize()
     // we may get the size of the control with the pane size summed up if we are expanded!
diff --git a/src/gtk/colordlg.cpp b/src/gtk/colordlg.cpp
index 2ee2cd2f92..a653741d7a 100644
--- a/src/gtk/colordlg.cpp
+++ b/src/gtk/colordlg.cpp
@@ -53,7 +53,7 @@ bool wxColourDialog::Create(wxWindow *parent, const wxColourData *data)
     gtk_color_chooser_set_use_alpha(GTK_COLOR_CHOOSER(m_widget), m_data.GetChooseAlpha());
 #else
     wxGCC_WARNING_SUPPRESS(deprecated-declarations)
-    m_widget = gtk_color_selection_dialog_new(wxGTK_CONV(title));
+    m_widget = gtk_color_selection_dialog_new(title.utf8_str());
 
     g_object_ref(m_widget);
 
diff --git a/src/gtk/colour.cpp b/src/gtk/colour.cpp
index bb5aedfc8d..41b2ae2a11 100644
--- a/src/gtk/colour.cpp
+++ b/src/gtk/colour.cpp
@@ -262,14 +262,14 @@ bool wxColour::FromString(const wxString& str)
 {
 #ifdef __WXGTK3__
     GdkRGBA gdkRGBA;
-    if (gdk_rgba_parse(&gdkRGBA, wxGTK_CONV_SYS(str)))
+    if (gdk_rgba_parse(&gdkRGBA, str.utf8_str()))
     {
         *this = wxColour(gdkRGBA);
         return true;
     }
 #else
     GdkColor colGDK;
-    if ( gdk_color_parse( wxGTK_CONV_SYS( str ), &colGDK ) )
+    if ( gdk_color_parse( str.utf8_str(), &colGDK ) )
     {
         *this = wxColour(colGDK);
         return true;
diff --git a/src/gtk/combobox.cpp b/src/gtk/combobox.cpp
index 2d7eae421c..01cdeb39bb 100644
--- a/src/gtk/combobox.cpp
+++ b/src/gtk/combobox.cpp
@@ -174,7 +174,7 @@ bool wxComboBox::Create( wxWindow *parent, wxWindowID id, const wxString& value,
         else // editable combobox
         {
             // any value is accepted, even if it's not in our list
-            gtk_entry_set_text( entry, wxGTK_CONV(value) );
+            gtk_entry_set_text( entry, value.utf8_str() );
         }
 
         GTKConnectChangedSignal();
diff --git a/src/gtk/control.cpp b/src/gtk/control.cpp
index a2b9945dae..f0cb37aac2 100644
--- a/src/gtk/control.cpp
+++ b/src/gtk/control.cpp
@@ -144,7 +144,7 @@ void wxControl::GTKFixSensitivity(bool WXUNUSED_IN_GTK3(onlyIfUnderMouse))
 void wxControl::GTKSetLabelForLabel(GtkLabel *w, const wxString& label)
 {
     const wxString labelGTK = GTKConvertMnemonics(label);
-    gtk_label_set_text_with_mnemonic(w, wxGTK_CONV(labelGTK));
+    gtk_label_set_text_with_mnemonic(w, labelGTK.utf8_str());
 }
 
 #if wxUSE_MARKUP
@@ -152,7 +152,7 @@ void wxControl::GTKSetLabelForLabel(GtkLabel *w, const wxString& label)
 void wxControl::GTKSetLabelWithMarkupForLabel(GtkLabel *w, const wxString& label)
 {
     const wxString labelGTK = GTKConvertMnemonicsWithMarkup(label);
-    gtk_label_set_markup_with_mnemonic(w, wxGTK_CONV(labelGTK));
+    gtk_label_set_markup_with_mnemonic(w, labelGTK.utf8_str());
 }
 
 #endif // wxUSE_MARKUP
@@ -168,7 +168,7 @@ void wxControl::GTKSetLabelWithMarkupForLabel(GtkLabel *w, const wxString& label
 GtkWidget* wxControl::GTKCreateFrame(const wxString& label)
 {
     const wxString labelGTK = GTKConvertMnemonics(label);
-    GtkWidget* labelwidget = gtk_label_new_with_mnemonic(wxGTK_CONV(labelGTK));
+    GtkWidget* labelwidget = gtk_label_new_with_mnemonic(labelGTK.utf8_str());
     gtk_widget_show(labelwidget); // without this it won't show...
 
     GtkWidget* framewidget = gtk_frame_new(nullptr);
diff --git a/src/gtk/dataview.cpp b/src/gtk/dataview.cpp
index 7d6f9a81e3..755c6ae680 100644
--- a/src/gtk/dataview.cpp
+++ b/src/gtk/dataview.cpp
@@ -2226,8 +2226,7 @@ static void wxGtkTextRendererEditedCallback( GtkCellRendererText *WXUNUSED(rende
 {
     wxDataViewRenderer *cell = (wxDataViewRenderer*) user_data;
 
-    cell->GtkOnTextEdited(arg1, wxGTK_CONV_BACK_FONT(
-                arg2, cell->GetOwner()->GetOwner()->GetFont()));
+    cell->GtkOnTextEdited(arg1, wxString::FromUTF8Unchecked(arg2));
 }
 
 }
@@ -2375,7 +2374,7 @@ const char* wxDataViewTextRenderer::GetTextPropertyName() const
 bool wxDataViewTextRenderer::SetTextValue(const wxString& str)
 {
     wxGtkValue gvalue( G_TYPE_STRING );
-    g_value_set_string( gvalue, wxGTK_CONV_FONT( str, GetOwner()->GetOwner()->GetFont() ) );
+    g_value_set_string( gvalue, str.utf8_str() );
     g_object_set_property( G_OBJECT(m_renderer), GetTextPropertyName(), gvalue );
 
     return true;
@@ -2385,7 +2384,7 @@ bool wxDataViewTextRenderer::GetTextValue(wxString& str) const
 {
     wxGtkValue gvalue( G_TYPE_STRING );
     g_object_get_property( G_OBJECT(m_renderer), GetTextPropertyName(), gvalue );
-    str = wxGTK_CONV_BACK_FONT( g_value_get_string( gvalue ), const_cast<wxDataViewTextRenderer*>(this)->GetOwner()->GetOwner()->GetFont() );
+    str = wxString::FromUTF8Unchecked( g_value_get_string( gvalue ) );
 
     return true;
 }
@@ -2787,7 +2786,7 @@ void wxDataViewCustomRenderer::RenderText( const wxString &text,
     GtkCellRendererText * const textRenderer = GtkGetTextRenderer();
 
     wxGtkValue gvalue( G_TYPE_STRING );
-    g_value_set_string( gvalue, wxGTK_CONV_FONT( text, GetOwner()->GetOwner()->GetFont() ) );
+    g_value_set_string( gvalue, text.utf8_str() );
     g_object_set_property( G_OBJECT(textRenderer), "text", gvalue );
 
     GtkApplyAttr(textRenderer, GetAttr());
@@ -2893,7 +2892,7 @@ void wxDataViewProgressRenderer::GTKSetLabel()
     if ( m_label.empty() )
         buf = wxScopedCharBuffer::CreateNonOwned("");
     else
-        buf = wxGTK_CONV_FONT(m_label, GetOwner()->GetOwner()->GetFont());
+        buf = m_label.utf8_str();
 
     g_value_set_string( gvalue, buf);
     g_object_set_property( G_OBJECT(m_renderer), "text", gvalue );
@@ -2983,9 +2982,7 @@ wxSize wxDataViewChoiceRenderer::GetSize() const
 bool wxDataViewChoiceRenderer::SetValue( const wxVariant &value )
 {
     wxGtkValue gvalue( G_TYPE_STRING );
-    g_value_set_string(gvalue,
-                       wxGTK_CONV_FONT(value.GetString(),
-                                       GetOwner()->GetOwner()->GetFont()));
+    g_value_set_string(gvalue, value.GetString().utf8_str());
     g_object_set_property( G_OBJECT(m_renderer), "text", gvalue );
 
     return true;
@@ -2995,8 +2992,7 @@ bool wxDataViewChoiceRenderer::GetValue( wxVariant &value ) const
 {
     wxGtkValue gvalue( G_TYPE_STRING );
     g_object_get_property( G_OBJECT(m_renderer), "text", gvalue );
-    value = wxGTK_CONV_BACK_FONT(g_value_get_string(gvalue),
-                                 GetOwner()->GetOwner()->GetFont());
+    value = wxString::FromUTF8Unchecked(g_value_get_string(gvalue));
 
     return true;
 }
@@ -3305,14 +3301,12 @@ void wxDataViewColumn::SetOwner( wxDataViewCtrl *owner )
 
     GtkTreeViewColumn *column = GTK_TREE_VIEW_COLUMN(m_column);
 
-    gtk_tree_view_column_set_title( column, wxGTK_CONV_FONT(GetTitle(), GetOwner()->GetFont() ) );
+    gtk_tree_view_column_set_title( column, GetTitle().utf8_str() );
 }
 
 void wxDataViewColumn::SetTitle( const wxString &title )
 {
-    wxDataViewCtrl *ctrl = GetOwner();
-    gtk_label_set_text( GTK_LABEL(m_label), ctrl ? wxGTK_CONV_FONT(title, ctrl->GetFont())
-                                                 : wxGTK_CONV_SYS(title) );
+    gtk_label_set_text( GTK_LABEL(m_label), title.utf8_str() );
     if (title.empty())
         gtk_widget_hide( m_label );
     else
@@ -3321,9 +3315,8 @@ void wxDataViewColumn::SetTitle( const wxString &title )
 
 wxString wxDataViewColumn::GetTitle() const
 {
-    return wxGTK_CONV_BACK_FONT(
-            gtk_label_get_text( GTK_LABEL(m_label) ),
-            GetOwner()->GetFont()
+    return wxString::FromUTF8Unchecked(
+            gtk_label_get_text( GTK_LABEL(m_label) )
            );
 }
 
diff --git a/src/gtk/dcclient.cpp b/src/gtk/dcclient.cpp
index 4d909d78d4..69478afc92 100644
--- a/src/gtk/dcclient.cpp
+++ b/src/gtk/dcclient.cpp
@@ -1385,7 +1385,7 @@ void wxWindowDCImpl::DoDrawRotatedText(const wxString& text, int xLogical, int y
 
     wxCHECK_RET( IsOk(), wxT("invalid window dc") );
 
-    pango_layout_set_text(m_layout, wxGTK_CONV(text), -1);
+    pango_layout_set_text(m_layout, text.utf8_str(), -1);
     const bool setAttrs = m_font.GTKSetPangoAttrs(m_layout);
 
     const GdkColor* bg_col = nullptr;
diff --git a/src/gtk/dirdlg.cpp b/src/gtk/dirdlg.cpp
index 03e6779286..8485cdf67f 100644
--- a/src/gtk/dirdlg.cpp
+++ b/src/gtk/dirdlg.cpp
@@ -89,17 +89,17 @@ bool wxDirDialog::Create(wxWindow* parent,
         gtk_parent = GTK_WINDOW( gtk_widget_get_toplevel(parent->m_widget) );
 
     m_widget = gtk_file_chooser_dialog_new(
-                   wxGTK_CONV(m_message),
+                   m_message.utf8_str(),
                    gtk_parent,
                    GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER,
 #ifdef __WXGTK4__
-                   static_cast<const char*>(wxGTK_CONV(wxConvertMnemonicsToGTK(wxGetStockLabel(wxID_CANCEL)))),
+                   static_cast<const char*>(wxConvertMnemonicsToGTK(wxGetStockLabel(wxID_CANCEL)).utf8_str()),
 #else
                    "gtk-cancel",
 #endif
                    GTK_RESPONSE_CANCEL,
 #ifdef __WXGTK4__
-                   static_cast<const char*>(wxGTK_CONV(wxConvertMnemonicsToGTK(wxGetStockLabel(wxID_OPEN)))),
+                   static_cast<const char*>(wxConvertMnemonicsToGTK(wxGetStockLabel(wxID_OPEN)).utf8_str()),
 #else
                    "gtk-open",
 #endif
diff --git a/src/gtk/filectrl.cpp b/src/gtk/filectrl.cpp
index e9c0db5654..8ff285710a 100644
--- a/src/gtk/filectrl.cpp
+++ b/src/gtk/filectrl.cpp
@@ -158,7 +158,7 @@ void wxGtkFileChooser::SetWildcard( const wxString& wildCard )
             {
                 GtkFileFilter* filter = gtk_file_filter_new();
 
-                gtk_file_filter_set_name( filter, wxGTK_CONV_SYS( wildDescriptions[n] ) );
+                gtk_file_filter_set_name( filter, wildDescriptions[n].utf8_str() );
 
                 wxStringTokenizer exttok( wildFilters[n], wxT( ";" ) );
 
@@ -166,7 +166,7 @@ void wxGtkFileChooser::SetWildcard( const wxString& wildCard )
                 while ( exttok.HasMoreTokens() )
                 {
                     wxString token = exttok.GetNextToken();
-                    gtk_file_filter_add_pattern( filter, wxGTK_CONV_SYS( token ) );
+                    gtk_file_filter_add_pattern( filter, token.utf8_str() );
 
                     if (n1 == 1)
                         m_wildcards.Add( token ); // Only add first pattern to list, used later when saving
@@ -422,7 +422,7 @@ bool wxGtkFileCtrl::SetFilename( const wxString& name )
 {
     if ( HasFlag( wxFC_SAVE ) )
     {
-        gtk_file_chooser_set_current_name( m_fcWidget, wxGTK_CONV( name ) );
+        gtk_file_chooser_set_current_name( m_fcWidget, name.utf8_str() );
         return true;
     }
     else
diff --git a/src/gtk/filedlg.cpp b/src/gtk/filedlg.cpp
index e2d334a3d2..8de91160be 100644
--- a/src/gtk/filedlg.cpp
+++ b/src/gtk/filedlg.cpp
@@ -235,16 +235,16 @@ bool wxFileDialog::Create(wxWindow *parent, const wxString& message,
     }
 
     m_widget = gtk_file_chooser_dialog_new(
-                   wxGTK_CONV(m_message),
+                   m_message.utf8_str(),
                    gtk_parent,
                    gtk_action,
 #ifdef __WXGTK4__
-                   static_cast<const gchar*>(wxGTK_CONV(wxConvertMnemonicsToGTK(wxGetStockLabel(wxID_CANCEL)))),
+                   static_cast<const gchar*>(wxConvertMnemonicsToGTK(wxGetStockLabel(wxID_CANCEL)).utf8_str()),
 #else
                    "gtk-cancel",
 #endif
                    GTK_RESPONSE_CANCEL,
-                   static_cast<const gchar*>(wxGTK_CONV(ok_btn_stock)), GTK_RESPONSE_ACCEPT,
+                   static_cast<const gchar*>(ok_btn_stock.utf8_str()), GTK_RESPONSE_ACCEPT,
                    nullptr);
 
     g_object_ref(m_widget);
@@ -448,7 +448,7 @@ void wxFileDialog::SetFilename(const wxString& name)
 
     if (HasFdFlag(wxFD_SAVE))
     {
-        gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(m_widget), wxGTK_CONV(name));
+        gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(m_widget), name.utf8_str());
     }
 
     else
diff --git a/src/gtk/font.cpp b/src/gtk/font.cpp
index fae6b3c6d6..41ae3457da 100644
--- a/src/gtk/font.cpp
+++ b/src/gtk/font.cpp
@@ -89,7 +89,7 @@ wxFontRefData::wxFontRefData(const wxFontInfo& info)
     if ( info.HasFaceName() )
     {
         pango_font_description_set_family( m_nativeFontInfo.description,
-                                           wxGTK_CONV_SYS(info.GetFaceName()) );
+                                           info.GetFaceName().utf8_str() );
     }
     else
     {
diff --git a/src/gtk/fontdlg.cpp b/src/gtk/fontdlg.cpp
index 28b3542dd6..f884ae6a73 100644
--- a/src/gtk/fontdlg.cpp
+++ b/src/gtk/fontdlg.cpp
@@ -84,12 +84,12 @@ bool wxFontDialog::DoCreate(wxWindow *parent)
     g_type_ensure(PANGO_TYPE_FONT_FACE);
 #endif
     if (gtk_check_version(3,2,0) == nullptr)
-        m_widget = gtk_font_chooser_dialog_new(wxGTK_CONV(message), gtk_parent);
+        m_widget = gtk_font_chooser_dialog_new(message.utf8_str(), gtk_parent);
     else
 #endif
     {
         wxGCC_WARNING_SUPPRESS(deprecated-declarations)
-        m_widget = gtk_font_selection_dialog_new(wxGTK_CONV(message));
+        m_widget = gtk_font_selection_dialog_new(message.utf8_str());
         if (gtk_parent)
             gtk_window_set_transient_for(GTK_WINDOW(m_widget), gtk_parent);
         wxGCC_WARNING_RESTORE()
@@ -114,7 +114,7 @@ bool wxFontDialog::DoCreate(wxWindow *parent)
                 wxGCC_WARNING_SUPPRESS(deprecated-declarations)
                 const wxString& fontname = info->ToString();
                 GtkFontSelectionDialog* sel = GTK_FONT_SELECTION_DIALOG(m_widget);
-                gtk_font_selection_dialog_set_font_name(sel, wxGTK_CONV(fontname));
+                gtk_font_selection_dialog_set_font_name(sel, fontname.utf8_str());
                 wxGCC_WARNING_RESTORE()
             }
         }
diff --git a/src/gtk/fontpicker.cpp b/src/gtk/fontpicker.cpp
index 03e54fb407..2b08f83a27 100644
--- a/src/gtk/fontpicker.cpp
+++ b/src/gtk/fontpicker.cpp
@@ -108,7 +108,7 @@ void wxFontButton::UpdateFont()
     const wxString& fontname = info->ToString();
 
     wxGCC_WARNING_SUPPRESS(deprecated-declarations)
-    gtk_font_button_set_font_name(GTK_FONT_BUTTON(m_widget), wxGTK_CONV(fontname));
+    gtk_font_button_set_font_name(GTK_FONT_BUTTON(m_widget), fontname.utf8_str());
     wxGCC_WARNING_RESTORE(deprecated-declarations)
 }
 
diff --git a/src/gtk/hyperlink.cpp b/src/gtk/hyperlink.cpp
index 421860ca52..43d9ca056a 100644
--- a/src/gtk/hyperlink.cpp
+++ b/src/gtk/hyperlink.cpp
@@ -181,7 +181,7 @@ void wxHyperlinkCtrl::SetLabel(const wxString &label)
     {
         wxControl::SetLabel(label);
         const wxString labelGTK = GTKConvertMnemonics(label);
-        gtk_button_set_label(GTK_BUTTON(m_widget), wxGTK_CONV(labelGTK));
+        gtk_button_set_label(GTK_BUTTON(m_widget), labelGTK.utf8_str());
     }
     else
         wxGenericHyperlinkCtrl::SetLabel(label);
@@ -190,7 +190,7 @@ void wxHyperlinkCtrl::SetLabel(const wxString &label)
 void wxHyperlinkCtrl::SetURL(const wxString &uri)
 {
     if ( UseNative() )
-        gtk_link_button_set_uri(GTK_LINK_BUTTON(m_widget), wxGTK_CONV(uri));
+        gtk_link_button_set_uri(GTK_LINK_BUTTON(m_widget), uri.utf8_str());
     else
         wxGenericHyperlinkCtrl::SetURL(uri);
 }
diff --git a/src/gtk/infobar.cpp b/src/gtk/infobar.cpp
index 4b96adae59..10a9c6247a 100644
--- a/src/gtk/infobar.cpp
+++ b/src/gtk/infobar.cpp
@@ -192,7 +192,7 @@ void wxInfoBar::ShowMessage(const wxString& msg, int flags)
     GtkMessageType type;
     if ( wxGTKImpl::ConvertMessageTypeFromWX(flags, &type) )
         gtk_info_bar_set_message_type(GTK_INFO_BAR(m_widget), type);
-    gtk_label_set_text(GTK_LABEL(m_impl->m_label), wxGTK_CONV(msg));
+    gtk_label_set_text(GTK_LABEL(m_impl->m_label), msg.utf8_str());
     gtk_label_set_line_wrap(GTK_LABEL(m_impl->m_label), TRUE );
 #if GTK_CHECK_VERSION(2,10,0)
     if( wx_is_at_least_gtk2( 10 ) )
@@ -234,9 +234,9 @@ GtkWidget *wxInfoBar::GTKAddButton(wxWindowID btnid, const wxString& label)
 
     GtkWidget* button = gtk_info_bar_add_button(GTK_INFO_BAR(m_widget),
 #ifdef __WXGTK4__
-        wxGTK_CONV(label.empty() ? wxConvertMnemonicsToGTK(wxGetStockLabel(btnid)) : label),
+        (label.empty() ? wxConvertMnemonicsToGTK(wxGetStockLabel(btnid)) : label).utf8_str(),
 #else
-        label.empty() ? wxGetStockGtkID(btnid) : static_cast<const char*>(wxGTK_CONV(label)),
+        label.empty() ? wxGetStockGtkID(btnid) : static_cast<const char*>(label.utf8_str()),
 #endif
         btnid);
 
diff --git a/src/gtk/listbox.cpp b/src/gtk/listbox.cpp
index 2201fe1c8c..53d4be47e6 100644
--- a/src/gtk/listbox.cpp
+++ b/src/gtk/listbox.cpp
@@ -450,7 +450,7 @@ int wxListBox::DoInsertItems(const wxArrayStringsAdapter& items,
 int wxListBox::DoInsertOneItem(const wxString& item, unsigned int pos)
 {
     wxTreeEntry* entry = wx_tree_entry_new();
-    wx_tree_entry_set_label(entry, wxGTK_CONV(item));
+    wx_tree_entry_set_label(entry, item.utf8_str());
     wx_tree_entry_set_destroy_func(entry, (wxTreeEntryDestroy)tree_entry_destroy_cb, this);
 
 #if wxUSE_CHECKLISTBOX
@@ -593,7 +593,7 @@ void wxListBox::SetString(unsigned int n, const wxString& label)
     wxTreeEntry* entry = GetEntry(m_liststore, &iter, this);
 
     // update the item itself
-    wx_tree_entry_set_label(entry, wxGTK_CONV(label));
+    wx_tree_entry_set_label(entry, label.utf8_str());
 
     // signal row changed
     GtkTreeModel* tree_model = GTK_TREE_MODEL(m_liststore);
@@ -608,7 +608,7 @@ wxString wxListBox::GetString(unsigned int n) const
     wxTreeEntry* entry = GTKGetEntry(n);
     wxCHECK_MSG( entry, wxEmptyString, wxT("wrong listbox index") );
 
-    return wxGTK_CONV_BACK(wx_tree_entry_get_label(entry));
+    return wxString::FromUTF8Unchecked(wx_tree_entry_get_label(entry));
 }
 
 unsigned int wxListBox::GetCount() const
diff --git a/src/gtk/mdi.cpp b/src/gtk/mdi.cpp
index ce187442e7..1c7c7bfb15 100644
--- a/src/gtk/mdi.cpp
+++ b/src/gtk/mdi.cpp
@@ -368,7 +368,7 @@ void wxMDIChildFrame::SetTitle( const wxString &title )
 
     GtkNotebook * const notebook = GTKGetNotebook();
     wxCHECK_RET( notebook, "no parent notebook?" );
-    gtk_notebook_set_tab_label_text(notebook, m_widget, wxGTK_CONV( title ) );
+    gtk_notebook_set_tab_label_text(notebook, m_widget, title.utf8_str() );
 }
 
 void wxMDIChildFrame::DoGetPosition(int *x, int *y) const
diff --git a/src/gtk/menu.cpp b/src/gtk/menu.cpp
index 6f40bb544d..2ef76ae8ea 100644
--- a/src/gtk/menu.cpp
+++ b/src/gtk/menu.cpp
@@ -348,7 +348,7 @@ void wxMenuBar::GtkAppend(wxMenu* menu, const wxString& title, int pos)
 
         const wxString str(wxConvertMnemonicsToGTK(title));
         // The "m_owner" is the "menu item"
-        menu->m_owner = gtk_menu_item_new_with_mnemonic( wxGTK_CONV( str ) );
+        menu->m_owner = gtk_menu_item_new_with_mnemonic( str.utf8_str() );
 
         gtk_menu_item_set_submenu( GTK_MENU_ITEM(menu->m_owner), menu->m_menu );
     }
@@ -533,7 +533,7 @@ void wxMenuBar::SetMenuLabel( size_t pos, const wxString& label )
 
     const wxString str(wxConvertMnemonicsToGTK(label));
     if (menu->m_owner)
-        gtk_label_set_text_with_mnemonic(GTK_LABEL(gtk_bin_get_child(GTK_BIN(menu->m_owner))), wxGTK_CONV(str));
+        gtk_label_set_text_with_mnemonic(GTK_LABEL(gtk_bin_get_child(GTK_BIN(menu->m_owner))), str.utf8_str());
 }
 
 //-----------------------------------------------------------------------------
@@ -682,7 +682,7 @@ void wxMenuItem::SetGtkLabel()
 {
     const wxString text = wxConvertMnemonicsToGTK(m_text.BeforeFirst('\t'));
     GtkLabel* label = GTK_LABEL(gtk_bin_get_child(GTK_BIN(m_menuItem)));
-    gtk_label_set_text_with_mnemonic(label, wxGTK_CONV_SYS(text));
+    gtk_label_set_text_with_mnemonic(label, text.utf8_str());
 #if wxUSE_ACCEL
     GtkAccel gtkAccel(this);
     if ( gtkAccel.IsOk() )
@@ -1366,7 +1366,7 @@ wxString GtkAccel::GetGtkHotKey(const wxAcceleratorEntry *accel)
                 if ( code < 127 )
                 {
                     const wxString
-                        name = wxGTK_CONV_BACK_SYS(gdk_keyval_name((guint)code));
+                        name = wxString::FromUTF8(gdk_keyval_name((guint)code));
                     if ( !name.empty() )
                     {
                         hotkey << name;
@@ -1410,7 +1410,7 @@ void GtkAccel::Init(const wxAcceleratorEntry* entry)
     const wxString string = GetGtkHotKey(entry);
     if (!string.empty())
     {
-        gtk_accelerator_parse(wxGTK_CONV_SYS(string), &m_key, &m_mods);
+        gtk_accelerator_parse(string.utf8_str(), &m_key, &m_mods);
 
         // Normally, we detect all the keys considered invalid by GTK in
         // GetGtkHotKey(), but just in case GTK decides to add more invalid
diff --git a/src/gtk/msgdlg.cpp b/src/gtk/msgdlg.cpp
index 3ac8995c16..c89babae0c 100644
--- a/src/gtk/msgdlg.cpp
+++ b/src/gtk/msgdlg.cpp
@@ -163,7 +163,7 @@ void wxMessageDialog::GTKCreateMsgDialog()
                                       type,
                                       buttons,
                                       "%s",
-                                      (const char*)wxGTK_CONV(message));
+                                      (const char*)message.utf8_str());
 
     if ( needsExtMessage )
     {
@@ -171,14 +171,14 @@ void wxMessageDialog::GTKCreateMsgDialog()
         (
             (GtkMessageDialog *)m_widget,
             "%s",
-            (const char *)wxGTK_CONV(m_extendedMessage)
+            (const char *)m_extendedMessage.utf8_str()
         );
     }
 
     g_object_ref(m_widget);
 
     if (m_caption != wxMessageBoxCaptionStr)
-        gtk_window_set_title(GTK_WINDOW(m_widget), wxGTK_CONV(m_caption));
+        gtk_window_set_title(GTK_WINDOW(m_widget), m_caption.utf8_str());
 
     GtkDialog * const dlg = GTK_DIALOG(m_widget);
 
@@ -196,7 +196,7 @@ void wxMessageDialog::GTKCreateMsgDialog()
     {
         if ( m_dialogStyle & wxHELP )
         {
-            gtk_dialog_add_button(dlg, wxGTK_CONV(GetHelpLabel()),
+            gtk_dialog_add_button(dlg, GetHelpLabel().utf8_str(),
                                   GTK_RESPONSE_HELP);
         }
 
@@ -208,24 +208,24 @@ void wxMessageDialog::GTKCreateMsgDialog()
             //
             // [Help]                  [Alternative] [Cancel] [Affirmative]
 
-            gtk_dialog_add_button(dlg, wxGTK_CONV(GetNoLabel()),
+            gtk_dialog_add_button(dlg, GetNoLabel().utf8_str(),
                                   GTK_RESPONSE_NO);
 
             if ( m_dialogStyle & wxCANCEL )
             {
-                gtk_dialog_add_button(dlg, wxGTK_CONV(GetCancelLabel()),
+                gtk_dialog_add_button(dlg, GetCancelLabel().utf8_str(),
                                       GTK_RESPONSE_CANCEL);
             }
 
-            gtk_dialog_add_button(dlg, wxGTK_CONV(GetYesLabel()),
+            gtk_dialog_add_button(dlg, GetYesLabel().utf8_str(),
                                   GTK_RESPONSE_YES);
         }
         else // Ok or Ok/Cancel dialog
         {
-            gtk_dialog_add_button(dlg, wxGTK_CONV(GetOKLabel()), GTK_RESPONSE_OK);
+            gtk_dialog_add_button(dlg, GetOKLabel().utf8_str(), GTK_RESPONSE_OK);
             if ( m_dialogStyle & wxCANCEL )
             {
-                gtk_dialog_add_button(dlg, wxGTK_CONV(GetCancelLabel()),
+                gtk_dialog_add_button(dlg, GetCancelLabel().utf8_str(),
                                       GTK_RESPONSE_CANCEL);
             }
         }
diff --git a/src/gtk/notebook.cpp b/src/gtk/notebook.cpp
index 7000309f99..73bfb74361 100644
--- a/src/gtk/notebook.cpp
+++ b/src/gtk/notebook.cpp
@@ -219,7 +219,7 @@ wxString wxNotebook::GetPageText( size_t page ) const
     wxCHECK_MSG(page < GetPageCount(), wxEmptyString, "invalid notebook index");
 
     GtkLabel* label = GTK_LABEL(GetNotebookPage(page)->m_label);
-    return wxGTK_CONV_BACK(gtk_label_get_text(label));
+    return wxString::FromUTF8(gtk_label_get_text(label));
 }
 
 int wxNotebook::GetPageImage( size_t page ) const
@@ -273,7 +273,7 @@ bool wxNotebook::SetPageText( size_t page, const wxString &text )
     wxCHECK_MSG(page < GetPageCount(), false, "invalid notebook index");
 
     GtkLabel* label = GTK_LABEL(GetNotebookPage(page)->m_label);
-    gtk_label_set_text(label, wxGTK_CONV(text));
+    gtk_label_set_text(label, text.utf8_str());
 
     return true;
 }
@@ -506,7 +506,7 @@ bool wxNotebook::InsertPage( size_t position,
     }
 
     /* set the label text */
-    pageData->m_label = gtk_label_new(wxGTK_CONV(wxStripMenuCodes(text)));
+    pageData->m_label = gtk_label_new(wxStripMenuCodes(text).utf8_str());
 
     if (m_windowStyle & wxBK_LEFT)
         gtk_label_set_angle(GTK_LABEL(pageData->m_label), 90);
diff --git a/src/gtk/radiobox.cpp b/src/gtk/radiobox.cpp
index b937d26a27..7dfce1a697 100644
--- a/src/gtk/radiobox.cpp
+++ b/src/gtk/radiobox.cpp
@@ -304,9 +304,9 @@ bool wxRadioBox::Create( wxWindow *parent, wxWindowID id, const wxString& title,
             label += *pc;
         }
         if ( hasMnemonic )
-            rbtn = GTK_RADIO_BUTTON( gtk_radio_button_new_with_mnemonic( radio_button_group, wxGTK_CONV( label ) ) );
+            rbtn = GTK_RADIO_BUTTON( gtk_radio_button_new_with_mnemonic( radio_button_group, label.utf8_str() ) );
         else
-            rbtn = GTK_RADIO_BUTTON( gtk_radio_button_new_with_label( radio_button_group, wxGTK_CONV( label ) ) );
+            rbtn = GTK_RADIO_BUTTON( gtk_radio_button_new_with_label( radio_button_group, label.utf8_str() ) );
 
         gtk_widget_show( GTK_WIDGET(rbtn) );
 
@@ -460,9 +460,7 @@ wxString wxRadioBox::GetString(unsigned int n) const
 
     GtkLabel* label = GTK_LABEL(gtk_bin_get_child(GTK_BIN(node->GetData()->button)));
 
-    wxString str( wxGTK_CONV_BACK( gtk_label_get_text(label) ) );
-
-    return str;
+    return wxString::FromUTF8Unchecked( gtk_label_get_text(label) );
 }
 
 void wxRadioBox::SetLabel( const wxString& label )
@@ -482,7 +480,7 @@ void wxRadioBox::SetString(unsigned int item, const wxString& label)
 
     GtkLabel* g_label = GTK_LABEL(gtk_bin_get_child(GTK_BIN(node->GetData()->button)));
 
-    gtk_label_set_text( g_label, wxGTK_CONV( label ) );
+    gtk_label_set_text( g_label, label.utf8_str() );
 }
 
 bool wxRadioBox::Enable( bool enable )
@@ -661,7 +659,7 @@ void wxRadioBox::DoSetItemToolTip(unsigned int n, wxToolTip *tooltip)
     if ( !tooltip )
         tooltip = GetToolTip();
     if ( tooltip )
-        buf = wxGTK_CONV(tooltip->GetTip());
+        buf = tooltip->GetTip().utf8_str();
 
     wxToolTip::GTKApply(GTK_WIDGET(m_buttonsInfo[n]->button), buf);
 }
diff --git a/src/gtk/radiobut.cpp b/src/gtk/radiobut.cpp
index d8491ead5a..604a699a25 100644
--- a/src/gtk/radiobut.cpp
+++ b/src/gtk/radiobut.cpp
@@ -92,7 +92,7 @@ bool wxRadioButton::Create( wxWindow *parent,
         }
     }
 
-    m_widget = gtk_radio_button_new_with_label( radioButtonGroup, wxGTK_CONV( label ) );
+    m_widget = gtk_radio_button_new_with_label( radioButtonGroup, label.utf8_str() );
     g_object_ref(m_widget);
 
     SetLabel(label);
diff --git a/src/gtk/spinctrl.cpp b/src/gtk/spinctrl.cpp
index 3b28a37ac5..823a40896f 100644
--- a/src/gtk/spinctrl.cpp
+++ b/src/gtk/spinctrl.cpp
@@ -307,7 +307,7 @@ wxString wxSpinCtrlGTKBase::GetTextValue() const
 {
     wxCHECK_MSG(m_widget, wxEmptyString, "invalid spin button");
 
-    return wxGTK_CONV_BACK(gtk_entry_get_text( GTK_ENTRY(m_widget) ));
+    return wxString::FromUTF8Unchecked(gtk_entry_get_text( GTK_ENTRY(m_widget) ));
 }
 
 bool wxSpinCtrlGTKBase::GetSnapToTicks() const
@@ -336,7 +336,7 @@ void wxSpinCtrlGTKBase::SetValue( const wxString& value )
     GTKSetTextOverride(value);
 
     wxSpinCtrlEventDisabler disable(this);
-    gtk_entry_set_text( GTK_ENTRY(m_widget), wxGTK_CONV( value ) );
+    gtk_entry_set_text( GTK_ENTRY(m_widget), value.utf8_str() );
 }
 
 void wxSpinCtrlGTKBase::DoSetValue( double value )
diff --git a/src/gtk/srchctrl.cpp b/src/gtk/srchctrl.cpp
index c7469df6da..9fb33b5f2c 100644
--- a/src/gtk/srchctrl.cpp
+++ b/src/gtk/srchctrl.cpp
@@ -177,7 +177,7 @@ bool wxSearchCtrl::Create(wxWindow *parent, wxWindowID id,
 
     PostCreation(size);
 
-    gtk_entry_set_text(entry, wxGTK_CONV(value));
+    gtk_entry_set_text(entry, value.utf8_str());
 
     SetHint(_("Search"));
 
diff --git a/src/gtk/textctrl.cpp b/src/gtk/textctrl.cpp
index 365c9f5898..ea97ffe52b 100644
--- a/src/gtk/textctrl.cpp
+++ b/src/gtk/textctrl.cpp
@@ -1136,7 +1136,7 @@ wxString wxTextCtrl::DoGetValue() const
         gtk_text_buffer_get_end_iter( m_buffer, &end );
         wxGtkString text(gtk_text_buffer_get_text(m_buffer, &start, &end, true));
 
-        return wxGTK_CONV_BACK(text);
+        return wxString::FromUTF8Unchecked(text);
     }
     else // single line
     {
@@ -1304,7 +1304,7 @@ wxString wxTextCtrl::GetLineText( long lineNo ) const
             gtk_text_iter_forward_to_line_end(&end);
 
         wxGtkString text(gtk_text_buffer_get_text(m_buffer, &line, &end, true));
-        result = wxGTK_CONV_BACK(text);
+        result = wxString::FromUTF8Unchecked(text);
     }
     else
     {
diff --git a/src/gtk/textentry.cpp b/src/gtk/textentry.cpp
index d83ce513e5..9fba8ebd9d 100644
--- a/src/gtk/textentry.cpp
+++ b/src/gtk/textentry.cpp
@@ -634,7 +634,7 @@ void wxTextEntry::WriteText(const wxString& value)
     gtk_editable_insert_text
     (
         edit,
-        wxGTK_CONV_FONT(value, GetEditableWindow()->GetFont()),
+        value.utf8_str(),
         -1,     // text: length: compute it using strlen()
         &len    // will be updated to position after the text end
     );
@@ -681,8 +681,7 @@ wxString wxTextEntry::DoGetValue() const
 {
     const wxGtkString value(gtk_editable_get_chars(GetEditable(), 0, -1));
 
-    return wxGTK_CONV_BACK_FONT(value,
-            const_cast<wxTextEntry *>(this)->GetEditableWindow()->GetFont());
+    return wxString::FromUTF8Unchecked(value);
 }
 
 void wxTextEntry::Remove(long from, long to)
@@ -1115,11 +1114,7 @@ bool wxTextEntry::SetHint(const wxString& hint)
     GtkEntry *entry = GetEntry();
     if (entry && gtk_check_version(3,2,0) == nullptr)
     {
-        gtk_entry_set_placeholder_text
-        (
-            entry,
-            wxGTK_CONV_FONT(hint, GetEditableWindow()->GetFont())
-        );
+        gtk_entry_set_placeholder_text(entry, hint.utf8_str());
         return true;
     }
 #endif
@@ -1132,11 +1127,7 @@ wxString wxTextEntry::GetHint() const
     GtkEntry *entry = GetEntry();
     if (entry && gtk_check_version(3,2,0) == nullptr)
     {
-        return wxGTK_CONV_BACK_FONT
-               (
-                gtk_entry_get_placeholder_text(entry),
-                const_cast<wxTextEntry *>(this)->GetEditableWindow()->GetFont()
-               );
+        return wxString::FromUTF8(gtk_entry_get_placeholder_text(entry));
     }
 #endif
     return wxTextEntryBase::GetHint();
diff --git a/src/gtk/textmeasure.cpp b/src/gtk/textmeasure.cpp
index c64b54b84b..20e35065ee 100644
--- a/src/gtk/textmeasure.cpp
+++ b/src/gtk/textmeasure.cpp
@@ -124,14 +124,7 @@ void wxTextMeasure::DoGetTextExtent(const wxString& string,
     }
 
     // Set layout's text
-    const wxCharBuffer dataUTF8 = wxGTK_CONV_FONT(string, GetFont());
-    if ( !dataUTF8 && !string.empty() )
-    {
-        // hardly ideal, but what else can we do if conversion failed?
-        wxLogLastError(wxT("GetTextExtent"));
-        return;
-    }
-    pango_layout_set_text(m_layout, dataUTF8, -1);
+    pango_layout_set_text(m_layout, string.utf8_str(), -1);
 
     if ( m_dc )
     {
@@ -170,15 +163,7 @@ bool wxTextMeasure::DoGetPartialTextExtents(const wxString& text,
         return wxTextMeasureBase::DoGetPartialTextExtents(text, widths, scaleX);
 
     // Set layout's text
-    const wxCharBuffer dataUTF8 = wxGTK_CONV_FONT(text, GetFont());
-    if ( !dataUTF8 )
-    {
-        // hardly ideal, but what else can we do if conversion failed?
-        wxLogLastError(wxT("GetPartialTextExtents"));
-        return false;
-    }
-
-    pango_layout_set_text(m_layout, dataUTF8, -1);
+    pango_layout_set_text(m_layout, text.utf8_str(), -1);
 
     // Calculate the position of each character based on the widths of
     // the previous characters
diff --git a/src/gtk/tglbtn.cpp b/src/gtk/tglbtn.cpp
index 6fad5d4240..b119af623d 100644
--- a/src/gtk/tglbtn.cpp
+++ b/src/gtk/tglbtn.cpp
@@ -177,7 +177,7 @@ void wxToggleButton::SetLabel(const wxString& label)
 
     const wxString labelGTK = GTKConvertMnemonics(label);
 
-    gtk_button_set_label(GTK_BUTTON(m_widget), wxGTK_CONV(labelGTK));
+    gtk_button_set_label(GTK_BUTTON(m_widget), labelGTK.utf8_str());
 
     GTKApplyWidgetStyle( false );
 }
diff --git a/src/gtk/toolbar.cpp b/src/gtk/toolbar.cpp
index 4c7fff5b9a..657e222064 100644
--- a/src/gtk/toolbar.cpp
+++ b/src/gtk/toolbar.cpp
@@ -350,7 +350,7 @@ void wxToolBarTool::SetLabel(const wxString& label)
         {
             wxString newLabel = wxControl::RemoveMnemonics(label);
             gtk_tool_button_set_label(GTK_TOOL_BUTTON(m_item),
-                                      wxGTK_CONV_SYS(newLabel));
+                                      newLabel.utf8_str());
             // To show the label for toolbar with wxTB_HORZ_LAYOUT.
             gtk_tool_item_set_is_important(m_item, true);
         }
@@ -587,7 +587,7 @@ bool wxToolBar::DoInsertTool(size_t pos, wxToolBarToolBase *toolBase)
                     label = wxControl::RemoveMnemonics(tool->GetLabel());
 
                 gtk_tool_button_set_label(
-                    GTK_TOOL_BUTTON(tool->m_item), wxGTK_CONV(label));
+                    GTK_TOOL_BUTTON(tool->m_item), label.utf8_str());
                 // needed for labels in horizontal toolbar with wxTB_HORZ_LAYOUT
                 gtk_tool_item_set_is_important(tool->m_item, true);
             }
@@ -597,14 +597,14 @@ bool wxToolBar::DoInsertTool(size_t pos, wxToolBarToolBase *toolBase)
                 if (wx_is_at_least_gtk2(12))
                 {
                     gtk_tool_item_set_tooltip_text(tool->m_item,
-                        wxGTK_CONV(tool->GetShortHelp()));
+                        tool->GetShortHelp().utf8_str());
                 }
                 else
 #endif
                 {
 #ifndef __WXGTK3__
                     gtk_tool_item_set_tooltip(tool->m_item,
-                        m_tooltips, wxGTK_CONV(tool->GetShortHelp()), "");
+                        m_tooltips, tool->GetShortHelp().utf8_str(), "");
 #endif
                 }
             }
@@ -775,14 +775,14 @@ void wxToolBar::SetToolShortHelp( int id, const wxString& helpString )
             if (wx_is_at_least_gtk2(12))
             {
                 gtk_tool_item_set_tooltip_text(tool->m_item,
-                    wxGTK_CONV(helpString));
+                    helpString.utf8_str());
             }
             else
 #endif
             {
 #ifndef __WXGTK3__
                 gtk_tool_item_set_tooltip(tool->m_item,
-                    m_tooltips, wxGTK_CONV(helpString), "");
+                    m_tooltips, helpString.utf8_str(), "");
 #endif
             }
         }
diff --git a/src/gtk/tooltip.cpp b/src/gtk/tooltip.cpp
index ece800189d..20555e1817 100644
--- a/src/gtk/tooltip.cpp
+++ b/src/gtk/tooltip.cpp
@@ -43,14 +43,14 @@ void wxToolTip::SetTip( const wxString &tip )
 {
     m_text = tip;
     if (m_window)
-        m_window->GTKApplyToolTip(wxGTK_CONV_SYS(m_text));
+        m_window->GTKApplyToolTip(m_text.utf8_str());
 }
 
 void wxToolTip::GTKSetWindow(wxWindow* win)
 {
     wxASSERT(win);
     m_window = win;
-    m_window->GTKApplyToolTip(wxGTK_CONV_SYS(m_text));
+    m_window->GTKApplyToolTip(m_text.utf8_str());
 }
 
 /* static */
diff --git a/src/gtk/toplevel.cpp b/src/gtk/toplevel.cpp
index a883dd8128..8b8905c767 100644
--- a/src/gtk/toplevel.cpp
+++ b/src/gtk/toplevel.cpp
@@ -721,10 +721,10 @@ bool wxTopLevelWindowGTK::Create( wxWindow *parent,
 
 #if 0
     if (!name.empty())
-        gtk_window_set_role( GTK_WINDOW(m_widget), wxGTK_CONV( name ) );
+        gtk_window_set_role( GTK_WINDOW(m_widget), name.utf8_str() );
 #endif
 
-    gtk_window_set_title( GTK_WINDOW(m_widget), wxGTK_CONV( title ) );
+    gtk_window_set_title( GTK_WINDOW(m_widget), title.utf8_str() );
     gtk_widget_set_can_focus(m_widget, false);
 
     g_signal_connect (m_widget, "delete_event",
@@ -1620,7 +1620,7 @@ void wxTopLevelWindowGTK::SetTitle( const wxString &title )
 
     m_title = title;
 
-    gtk_window_set_title( GTK_WINDOW(m_widget), wxGTK_CONV( title ) );
+    gtk_window_set_title( GTK_WINDOW(m_widget), title.utf8_str() );
 }
 
 void wxTopLevelWindowGTK::SetIcons( const wxIconBundle &icons )
diff --git a/src/gtk/webview_webkit.cpp b/src/gtk/webview_webkit.cpp
index 780f220311..574028d9fe 100644
--- a/src/gtk/webview_webkit.cpp
+++ b/src/gtk/webview_webkit.cpp
@@ -576,7 +576,7 @@ void wxWebViewWebKit::Reload(wxWebViewReloadFlags flags)
 
 void wxWebViewWebKit::LoadURL(const wxString& url)
 {
-    webkit_web_view_load_uri(m_web_view, wxGTK_CONV(url));
+    webkit_web_view_load_uri(m_web_view, url.utf8_str());
 }
 
 
@@ -986,7 +986,7 @@ long wxWebViewWebKit::Find(const wxString& text, int flags)
     if(newSearch)
     {
         //Initially we mark the matches to know how many we have
-        m_findCount = webkit_web_view_mark_text_matches(m_web_view, wxGTK_CONV(text), matchCase, 0);
+        m_findCount = webkit_web_view_mark_text_matches(m_web_view, text.utf8_str(), matchCase, 0);
         //In this case we return early to match IE behaviour
         m_findPosition = -1;
         return m_findCount;
@@ -1007,7 +1007,7 @@ long wxWebViewWebKit::Find(const wxString& text, int flags)
     bool highlight = flags & wxWEBVIEW_FIND_HIGHLIGHT_RESULT ? true : false;
     webkit_web_view_set_highlight_text_matches(m_web_view, highlight);     
 
-    if(!webkit_web_view_search_text(m_web_view, wxGTK_CONV(text), matchCase, forward, wrap))
+    if(!webkit_web_view_search_text(m_web_view, text.utf8_str(), matchCase, forward, wrap))
     {
         m_findPosition = -1;
         ClearSelection();
diff --git a/src/gtk/webview_webkit2.cpp b/src/gtk/webview_webkit2.cpp
index 05be96a2e4..251f6ebc2c 100644
--- a/src/gtk/webview_webkit2.cpp
+++ b/src/gtk/webview_webkit2.cpp
@@ -801,7 +801,7 @@ void wxWebViewWebKit::Reload(wxWebViewReloadFlags flags)
 
 void wxWebViewWebKit::LoadURL(const wxString& url)
 {
-    webkit_web_view_load_uri(m_web_view, wxGTK_CONV(url));
+    webkit_web_view_load_uri(m_web_view, url.utf8_str());
 }
 
 
@@ -1417,7 +1417,7 @@ long wxWebViewWebKit::Find(const wxString& text, int flags)
         //Initially we count the matches to know how many we have
         m_findCount = -1;
         webkit_find_controller_count_matches(findctrl,
-                                             wxGTK_CONV(text),
+                                             text.utf8_str(),
                                              options,
                                              G_MAXUINT);
         GMainContext *main_context = g_main_context_get_thread_default();
@@ -1429,7 +1429,7 @@ long wxWebViewWebKit::Find(const wxString& text, int flags)
         if(flags & wxWEBVIEW_FIND_HIGHLIGHT_RESULT)
         {
             webkit_find_controller_search(findctrl,
-                                          wxGTK_CONV(text),
+                                          text.utf8_str(),
                                           options,
                                           G_MAXUINT);
         }
diff --git a/src/gtk/window.cpp b/src/gtk/window.cpp
index f6aaf4fb5a..338f182fea 100644
--- a/src/gtk/window.cpp
+++ b/src/gtk/window.cpp
@@ -1350,7 +1350,7 @@ bool wxWindowGTK::GTKDoInsertTextFromIM(const char* str)
         event.SetEventObject(this);
     }
 
-    const wxString data(wxGTK_CONV_BACK_SYS(str));
+    const wxString data(wxString::FromUTF8Unchecked(str));
     if( data.empty() )
         return false;
 
diff --git a/src/unix/fontutil.cpp b/src/unix/fontutil.cpp
index 793e26fd2d..d36f7b5794 100644
--- a/src/unix/fontutil.cpp
+++ b/src/unix/fontutil.cpp
@@ -44,17 +44,14 @@ PangoContext* wxGetPangoContext();
 
 #ifdef __WXGTK__
     #include "wx/gtk/private.h"
-
-    #define wxPANGO_CONV wxGTK_CONV_SYS
-    #define wxPANGO_CONV_BACK wxGTK_CONV_BACK_SYS
 #else
     #include "wx/x11/private.h"
     #include "wx/gtk/private/string.h"
-
-    #define wxPANGO_CONV(s) s.utf8_str()
-    #define wxPANGO_CONV_BACK(s) wxString::FromUTF8Unchecked(s)
 #endif
 
+#define wxPANGO_CONV(s) s.utf8_str()
+#define wxPANGO_CONV_BACK(s) wxString::FromUTF8Unchecked(s)
+
 // ----------------------------------------------------------------------------
 // wxNativeFontInfo
 // ----------------------------------------------------------------------------
diff --git a/src/x11/font.cpp b/src/x11/font.cpp
index 833a312cde..62f7b82f92 100644
--- a/src/x11/font.cpp
+++ b/src/x11/font.cpp
@@ -211,7 +211,7 @@ void wxFontRefData::InitFromNative()
     PangoFontDescription *desc = m_nativeFontInfo.description;
 
     // init fields
-    m_faceName = wxGTK_CONV_BACK( pango_font_description_get_family( desc ) );
+    m_faceName = wxString::FromUTF8( pango_font_description_get_family( desc ) );
 
     m_pointSize = static_cast<float>(pango_font_description_get_size( desc )) / PANGO_SCALE;
 
@@ -378,7 +378,7 @@ bool wxFont::Create(int pointSize,
     return true;
 }
 
-bool wxFont::Create(const wxString& fontname, wxFontEncoding enc)
+bool wxFont::Create(const wxString& fontname, wxFontEncoding WXUNUSED(enc))
 {
     if( !fontname )
     {