diff --git a/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp b/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp
--- a/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp
+++ b/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp
@@ -219,8 +219,6 @@
   return Ret;
 }
 bool IncludeCategoryManager::isMainHeader(StringRef IncludeName) const {
-  if (!IncludeName.startswith("\""))
-    return false;
   StringRef HeaderStem =
       llvm::sys::path::stem(IncludeName.drop_front(1).drop_back(1));
   if (FileStem.startswith(HeaderStem) ||