diff --git a/include/wx/richtext/richtextxml.h b/include/wx/richtext/richtextxml.h
index 67b76b6830..5ca8b1c0ab 100644
--- a/include/wx/richtext/richtextxml.h
+++ b/include/wx/richtext/richtextxml.h
@@ -15,7 +15,6 @@
  * Includes
  */
 
-#include "wx/hashmap.h"
 #include "wx/richtext/richtextbuffer.h"
 #include "wx/richtext/richtextstyles.h"
 
@@ -217,12 +216,12 @@ public:
         Call with XML node name, C++ class name so that wxRTC can read in the node.
         If you add a custom object, call this.
     */
-    static void RegisterNodeName(const wxString& nodeName, const wxString& className) { sm_nodeNameToClassMap[nodeName] = className; }
+    static void RegisterNodeName(const wxString& nodeName, const wxString& className);
 
     /**
         Cleans up the mapping between node name and C++ class.
     */
-    static void ClearNodeToClassMap() { sm_nodeNameToClassMap.clear(); }
+    static void ClearNodeToClassMap();
 
 protected:
 #if wxUSE_STREAMS
@@ -231,8 +230,6 @@ protected:
 #endif
 
     wxRichTextXMLHelper m_helper;
-
-    static wxStringToStringHashMap sm_nodeNameToClassMap;
 };
 
 #endif
diff --git a/src/richtext/richtextxml.cpp b/src/richtext/richtextxml.cpp
index 4814650ab8..91a2f65973 100644
--- a/src/richtext/richtextxml.cpp
+++ b/src/richtext/richtextxml.cpp
@@ -32,6 +32,8 @@
 #include "wx/stopwatch.h"
 #include "wx/xml/xml.h"
 
+#include <unordered_map>
+
 // Set to 1 for slower wxXmlDocument method, 0 for faster direct method.
 // If we make wxXmlDocument::Save more efficient, we might switch to this
 // method.
@@ -50,7 +52,12 @@
 
 wxIMPLEMENT_DYNAMIC_CLASS(wxRichTextXMLHandler, wxRichTextFileHandler);
 
-wxStringToStringHashMap wxRichTextXMLHandler::sm_nodeNameToClassMap;
+namespace
+{
+
+std::unordered_map<wxString, wxString> gs_nodeNameToClassMap;
+
+} // anonymous namespace
 
 void wxRichTextXMLHandler::Init()
 {
@@ -111,12 +118,22 @@ bool wxRichTextXMLHandler::DoLoadFile(wxRichTextBuffer *buffer, wxInputStream& s
     return success;
 }
 
+void wxRichTextXMLHandler::RegisterNodeName(const wxString& nodeName, const wxString& className)
+{
+    gs_nodeNameToClassMap[nodeName] = className;
+}
+
+void wxRichTextXMLHandler::ClearNodeToClassMap()
+{
+    gs_nodeNameToClassMap.clear();
+}
+
 /// Creates an object given an XML element name
 wxRichTextObject* wxRichTextXMLHandler::CreateObjectForXMLName(wxRichTextObject* WXUNUSED(parent), const wxString& name) const
 {
     // The standard node to class mappings are added in wxRichTextModule::OnInit in richtextbuffer.cpp
-    wxStringToStringHashMap::const_iterator it = sm_nodeNameToClassMap.find(name);
-    if (it == sm_nodeNameToClassMap.end())
+    const auto it = gs_nodeNameToClassMap.find(name);
+    if (it == gs_nodeNameToClassMap.end())
         return nullptr;
     else
         return wxDynamicCast(wxCreateDynamicObject(it->second), wxRichTextObject);