diff --git a/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj b/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj
index 9ec7f9f..9c08c8b 100644
--- a/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj
+++ b/objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj
@@ -999,6 +999,7 @@
 					"-Wreserved-id-macro",
 					"-Wswitch-enum",
 					"-Wdirect-ivar-access",
+					"-Woverriding-method-mismatch",
 				);
 			};
 			name = Debug;
@@ -1056,6 +1057,7 @@
 					"-Wreserved-id-macro",
 					"-Wswitch-enum",
 					"-Wdirect-ivar-access",
+					"-Woverriding-method-mismatch",
 				);
 			};
 			name = Release;