diff --git a/rts/sm/MarkStack.h b/rts/sm/MarkStack.h
index db79ca452082..e2319a544d47 100644
--- a/rts/sm/MarkStack.h
+++ b/rts/sm/MarkStack.h
@@ -12,7 +12,7 @@
  * ---------------------------------------------------------------------------*/
 
 #ifndef SM_MARKSTACK_H
-#define SM_MARKSTACk_H
+#define SM_MARKSTACK_H
 
 #include "BeginPrivate.h"