diff --git a/Foundation/include/Poco/UnWindows.h b/Foundation/include/Poco/UnWindows.h
index d3af018eb..b0f406a76 100644
--- a/Foundation/include/Poco/UnWindows.h
+++ b/Foundation/include/Poco/UnWindows.h
@@ -88,7 +88,7 @@
 #undef UpdateResource
 #undef FindAtom
 #undef AddAtom
-#undef GetSystemDirector
+#undef GetSystemDirectory
 #undef GetTempPath
 #undef GetTempFileName
 #undef SetCurrentDirectory