diff --git a/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h b/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h
index 29fff9f4f5e..b75123eaca4 100644
--- a/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h
+++ b/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h
@@ -70,7 +70,7 @@
 
 
 #include <windows.h>
-#include <GL\gl.h>
+#include <GL/gl.h>
 #include "context.h"
 #ifdef DDRAW
 #define DIRECTDRAW_VERSION 0x0100
diff --git a/reactos/lib/mesa32/src/drivers/windows/icd/wmesadef.h b/reactos/lib/mesa32/src/drivers/windows/icd/wmesadef.h
index 430da91fe14..f2f8ebe7e6b 100644
--- a/reactos/lib/mesa32/src/drivers/windows/icd/wmesadef.h
+++ b/reactos/lib/mesa32/src/drivers/windows/icd/wmesadef.h
@@ -70,7 +70,7 @@
 
 
 #include <windows.h>
-#include <GL\gl.h>
+#include <GL/gl.h>
 #include "context.h"
 #ifdef DDRAW
 #define DIRECTDRAW_VERSION 0x0100