diff --git a/dlls/atl/atlwin.h b/dlls/atl/atlwin.h
index 8a9357d8090..4bd13599667 100644
--- a/dlls/atl/atlwin.h
+++ b/dlls/atl/atlwin.h
@@ -18,6 +18,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#ifndef __WINE_ATLWIN_H__
+#define __WINE_ATLWIN_H__
+
 typedef struct _ATL_WNDCLASSINFOA_TAG
 {
     WNDCLASSEXA m_wc;
@@ -46,3 +49,5 @@ ATOM WINAPI AtlModuleRegisterWndClassInfoW(_ATL_MODULEW *pm, _ATL_WNDCLASSINFOW
 HDC WINAPI AtlCreateTargetDC(HDC hdc, DVTARGETDEVICE *ptd);
 void WINAPI AtlHiMetricToPixel(const SIZEL *lpSizeInHiMetric, LPSIZEL lpSizeInPix);
 void WINAPI AtlPixelToHiMetric(const SIZEL *lpSizeInPix, LPSIZEL lpSizeInHiMetric);
+
+#endif /* __WINE_ATLWIN_H__ */