diff --git a/Source/cmQtAutomoc.cxx b/Source/cmQtAutomoc.cxx
index 6e8c77e7c..316d82411 100644
--- a/Source/cmQtAutomoc.cxx
+++ b/Source/cmQtAutomoc.cxx
@@ -140,6 +140,8 @@ void cmQtAutomoc::SetupAutomocTarget(cmMakefile* makefile,
   makefile->GetOrCreateSource(mocCppFile.c_str(), true);
   srcs.push_back(mocCppFile);
 
+  makefile->AppendProperty("ADDITIONAL_MAKE_CLEAN_FILES",
+                           mocCppFile.c_str(), false);
 }