diff --git a/tests/strings/vsnprintf.cpp b/tests/strings/vsnprintf.cpp
index ca6d276d2b..015480e869 100644
--- a/tests/strings/vsnprintf.cpp
+++ b/tests/strings/vsnprintf.cpp
@@ -19,6 +19,8 @@
     #pragma hdrstop
 #endif
 
+#include "wx/crt.h"
+
 #if wxUSE_WXVSNPRINTF
 
 #ifndef WX_PRECOMP