diff --git a/docs/changes.txt b/docs/changes.txt
index f262050a77..6418898b8f 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -46,6 +46,9 @@ Changes in behaviour which may result in build errors
 - wxMotif and wxGTK1 ports have been removed, please use wxWidgets 3.2 if you
   still need them.
 
+- wxOnAssert() overload taking wide character file name was removed. If you
+  call it for any reason, please use one of the other overloads instead.
+
 
 3.3.0: (released 2022-??-??)
 ----------------------------
diff --git a/include/wx/debug.h b/include/wx/debug.h
index a8ca42e599..c82ff5de24 100644
--- a/include/wx/debug.h
+++ b/include/wx/debug.h
@@ -190,15 +190,6 @@ extern WXDLLIMPEXP_BASE void wxOnAssert(const char *file,
                                         const char *cond,
                                         const wxChar *msg) ;
 
-// this version is for compatibility with wx 2.8 Unicode build only, we don't
-// use it ourselves any more except in ANSI-only build in which case it is all
-// we need
-extern WXDLLIMPEXP_BASE void wxOnAssert(const wxChar *file,
-                                        int line,
-                                        const char *func,
-                                        const wxChar *cond,
-                                        const wxChar *msg = nullptr);
-
 // these overloads work when msg passed to debug macro is a string and we
 // also have to provide wxCStrData overload to resolve ambiguity which would
 // otherwise arise from wxASSERT( s.c_str() )
diff --git a/src/common/appbase.cpp b/src/common/appbase.cpp
index 316237a513..1467372f4c 100644
--- a/src/common/appbase.cpp
+++ b/src/common/appbase.cpp
@@ -1165,19 +1165,6 @@ void wxOnAssert(const wxString& file,
     wxTheAssertHandler(file, line, func, cond, wxString());
 }
 
-void wxOnAssert(const wxChar *file,
-                int line,
-                const char *func,
-                const wxChar *cond,
-                const wxChar *msg)
-{
-    // this is the backwards-compatible version
-    // so it could be called directly from the user code and this might happen
-    // even when wxTheAssertHandler is null
-    if ( wxTheAssertHandler )
-        wxTheAssertHandler(file, line, func, cond, msg);
-}
-
 void wxOnAssert(const char *file,
                 int line,
                 const char *func,