diff --git a/src/engine/helper/HL_String.h b/src/engine/helper/HL_String.h
index 15f52764..f30b5052 100644
--- a/src/engine/helper/HL_String.h
+++ b/src/engine/helper/HL_String.h
@@ -9,6 +9,7 @@
 #include <vector>
 #include <string>
 #include <sstream>
+#include <stdint.h>
 #include "HL_Types.h"
 
 #ifdef TARGET_OSX