diff --git a/include/wx/colour.h b/include/wx/colour.h
index 0be6fe1e4e..2957aa861a 100644
--- a/include/wx/colour.h
+++ b/include/wx/colour.h
@@ -13,6 +13,7 @@
 
 #include "wx/defs.h"
 #include "wx/gdiobj.h"
+#include "wx/string.h"
 #include "wx/variant.h"
 
 class WXDLLIMPEXP_FWD_CORE wxColour;