diff --git a/Contrib/zip2exe/main.cpp b/Contrib/zip2exe/main.cpp
index 8cbebef0..08d9fdc9 100644
--- a/Contrib/zip2exe/main.cpp
+++ b/Contrib/zip2exe/main.cpp
@@ -1,5 +1,6 @@
 #include <windows.h>
 #include <stdio.h>
+#include <ctype.h>
 #include <commctrl.h>
 
 /*