diff --git a/clang-tools-extra/clang-tidy/objc/ForbiddenSubclassingCheck.cpp b/clang-tools-extra/clang-tidy/objc/ForbiddenSubclassingCheck.cpp
index a8d79f5..e78cb99 100644
--- a/clang-tools-extra/clang-tidy/objc/ForbiddenSubclassingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/objc/ForbiddenSubclassingCheck.cpp
@@ -77,6 +77,10 @@
 }
 
 void ForbiddenSubclassingCheck::registerMatchers(MatchFinder *Finder) {
+  // this check should only be applied to ObjC sources.
+  if (!getLangOpts().ObjC1 && !getLangOpts().ObjC2) {
+    return;
+  }
   Finder->addMatcher(
       objcInterfaceDecl(
           isSubclassOf(