diff --git a/include/wx/stackwalk.h b/include/wx/stackwalk.h
index 1133d6ef7c..c0ba151d75 100644
--- a/include/wx/stackwalk.h
+++ b/include/wx/stackwalk.h
@@ -15,6 +15,8 @@
 
 #if wxUSE_STACKWALKER
 
+#include "wx/string.h"
+
 class WXDLLIMPEXP_FWD_BASE wxStackFrame;
 
 #define wxSTACKWALKER_MAX_DEPTH       (200)