diff --git a/include/wx/xml/xml.h b/include/wx/xml/xml.h
index 67fe18bf7c..023337ce33 100644
--- a/include/wx/xml/xml.h
+++ b/include/wx/xml/xml.h
@@ -132,7 +132,7 @@ public:
     const wxString& GetContent() const { return m_content; }
 
     bool IsWhitespaceOnly() const;
-    int GetDepth(wxXmlNode *grandparent = nullptr) const;
+    int GetDepth(const wxXmlNode *grandparent = nullptr) const;
 
     // Gets node content from wxXML_ENTITY_NODE
     // The problem is, <tag>content<tag> is represented as
diff --git a/interface/wx/xml/xml.h b/interface/wx/xml/xml.h
index 6477391cc9..d2afbe3e5f 100644
--- a/interface/wx/xml/xml.h
+++ b/interface/wx/xml/xml.h
@@ -203,7 +203,7 @@ public:
         @a grandparent or the @NULL node (which is the parent of non-linked
         nodes or the parent of a wxXmlDocument's root element node).
     */
-    int GetDepth(wxXmlNode* grandparent = nullptr) const;
+    int GetDepth(const wxXmlNode* grandparent = nullptr) const;
 
     /**
         Returns a flag indicating whether encoding conversion is necessary when saving. The default is @false.
diff --git a/src/xml/xml.cpp b/src/xml/xml.cpp
index bd1c64526b..d8e4ae5199 100644
--- a/src/xml/xml.cpp
+++ b/src/xml/xml.cpp
@@ -361,7 +361,7 @@ wxString wxXmlNode::GetNodeContent() const
     return wxEmptyString;
 }
 
-int wxXmlNode::GetDepth(wxXmlNode *grandparent) const
+int wxXmlNode::GetDepth(const wxXmlNode *grandparent) const
 {
     const wxXmlNode *n = this;
     int ret = -1;