diff --git a/python/core/qgsrasterlayer.sip b/python/core/qgsrasterlayer.sip
index 1d4caed26be..1aa590d4fd5 100644
--- a/python/core/qgsrasterlayer.sip
+++ b/python/core/qgsrasterlayer.sip
@@ -489,7 +489,7 @@ public:
     bool readXml( QDomNode & layer_node );
 
     /** \brief Write the symbology for the layer into the docment provided */
-    bool writeSymbology( QDomNode&, QDomDocument& doc, QString& errorMessage );
+    bool writeSymbology( QDomNode&, QDomDocument& doc, QString& errorMessage ) const;
 
     /** \brief Write layer specific state to project file Dom node */
     bool writeXml( QDomNode & layer_node, QDomDocument & doc );
diff --git a/python/core/qgsvectorlayer.sip b/python/core/qgsvectorlayer.sip
index 6c401962c0a..7402014bb0f 100644
--- a/python/core/qgsvectorlayer.sip
+++ b/python/core/qgsvectorlayer.sip
@@ -130,7 +130,7 @@ public:
    * @param errorMessage reference to string that will be updated with any error messages
    *  @return true in case of success.
    */
-  bool writeSymbology(QDomNode&, QDomDocument& doc, QString& errorMessage);
+  bool writeSymbology(QDomNode&, QDomDocument& doc, QString& errorMessage) const;
 
   /**
    * Number of features in the layer. This is necessary if features are