diff --git a/QPropertyModel.pro b/QPropertyModel.pro
index 38be5c6..af956e2 100644
--- a/QPropertyModel.pro
+++ b/QPropertyModel.pro
@@ -14,7 +14,7 @@ CONFIG += debug_and_release
 DEFINES += QPROPERTYMODEL_LIBRARY
 
 *msvc* { # visual studio spec filter
-      QMAKE_CXXFLAGS += -MP
+      QMAKE_CXXFLAGS += /MP
   }
 
 contains(DEFINES,QPROPERTYMODEL_LIBRARY){