Index: clang-tidy/llvm/HeaderGuardCheck.h
===================================================================
--- clang-tidy/llvm/HeaderGuardCheck.h
+++ clang-tidy/llvm/HeaderGuardCheck.h
@@ -17,13 +17,27 @@
 namespace llvm {
 
 /// Finds and fixes header guards that do not adhere to LLVM style.
+/// The check supports these options:
+///   - `HeaderFileExtensions`: a comma-separated list of filename extensions of
+///     header files (The filename extension should not contain "." prefix).
+///     ",h,hh,hpp,hxx" by default.
+///     For extension-less header files, using an empty string or leaving an
+///     empty string between "," if there are other filename extensions.
 class LLVMHeaderGuardCheck : public utils::HeaderGuardCheck {
 public:
   LLVMHeaderGuardCheck(StringRef Name, ClangTidyContext *Context)
-      : HeaderGuardCheck(Name, Context) {}
+      : HeaderGuardCheck(Name, Context), RawStringHeaderFileExtensions(
+          Options.getLocalOrGlobal("HeaderFileExtensions", ",h,hh,hpp,hxx")) {
+      utils::parseHeaderFileExtensions(RawStringHeaderFileExtensions,
+                                           HeaderFileExtensions,
+                                           ',');
+  }
   bool shouldSuggestEndifComment(StringRef Filename) override { return false; }
   bool shouldFixHeaderGuard(StringRef Filename) override;
   std::string getHeaderGuard(StringRef Filename, StringRef OldGuard) override;
+private:
+  std::string RawStringHeaderFileExtensions;
+  utils::HeaderFileExtensionsSet HeaderFileExtensions;
 };
 
 } // namespace llvm
Index: clang-tidy/llvm/HeaderGuardCheck.cpp
===================================================================
--- clang-tidy/llvm/HeaderGuardCheck.cpp
+++ clang-tidy/llvm/HeaderGuardCheck.cpp
@@ -14,7 +14,15 @@
 namespace llvm {
 
 bool LLVMHeaderGuardCheck::shouldFixHeaderGuard(StringRef Filename) {
-  return Filename.endswith(".h");
+  StringRef extension = ::llvm::sys::path::extension(Filename);
+  if (extension.size() > 0 && extension.front() == '.') {
+    extension = extension.substr(1);
+  }
+
+  if (HeaderFileExtensions.count(extension))
+    return true;
+
+  return false;
 }
 
 std::string LLVMHeaderGuardCheck::getHeaderGuard(StringRef Filename,
Index: clang-tidy/utils/HeaderFileExtensionsUtils.h
===================================================================
--- clang-tidy/utils/HeaderFileExtensionsUtils.h
+++ clang-tidy/utils/HeaderFileExtensionsUtils.h
@@ -41,6 +41,10 @@
                                HeaderFileExtensionsSet &HeaderFileExtensions,
                                char delimiter);
 
+/// \brief Decides whether a file has a header file extension
+bool isHeaderFileExtension(StringRef FileName,
+                           HeaderFileExtensionsSet HeaderFileExtensions);
+
 } // namespace utils
 } // namespace tidy
 } // namespace clang
Index: clang-tidy/utils/HeaderFileExtensionsUtils.cpp
===================================================================
--- clang-tidy/utils/HeaderFileExtensionsUtils.cpp
+++ clang-tidy/utils/HeaderFileExtensionsUtils.cpp
@@ -61,6 +61,17 @@
   return true;
 }
 
+bool isHeaderFileExtension(StringRef FileName, HeaderFileExtensionsSet HeaderFileExtensions) {
+  StringRef extension = ::llvm::sys::path::extension(FileName);
+  if (extension.size() > 0 && extension.front() == '.') {
+    extension = extension.substr(1);
+  }
+  if (HeaderFileExtensions.count(extension))
+    return true;
+
+  return false;
+}
+
 } // namespace utils
 } // namespace tidy
 } // namespace clang
Index: clang-tidy/utils/HeaderGuard.h
===================================================================
--- clang-tidy/utils/HeaderGuard.h
+++ clang-tidy/utils/HeaderGuard.h
@@ -11,16 +11,29 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_HEADERGUARD_H
 
 #include "../ClangTidy.h"
+#include "../utils/HeaderFileExtensionsUtils.h"
+#include "llvm/Support/Path.h"
 
 namespace clang {
 namespace tidy {
 namespace utils {
 
 /// Finds and fixes header guards.
+/// The check supports these options:
+///   - `HeaderFileExtensions`: a comma-separated list of filename extensions of
+///     header files (The filename extension should not contain "." prefix).
+///     ",h,hh,hpp,hxx" by default.
+///     For extension-less header files, using an empty string or leaving an
+///     empty string between "," if there are other filename extensions.
 class HeaderGuardCheck : public ClangTidyCheck {
 public:
   HeaderGuardCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+      : ClangTidyCheck(Name, Context),
+        RawStringHeaderFileExtensions(
+          Options.getLocalOrGlobal("HeaderFileExtensions", ",h,hh,hpp,hxx")) {
+    utils::parseHeaderFileExtensions(RawStringHeaderFileExtensions,
+                                     HeaderFileExtensions, ',');
+  }
   void registerPPCallbacks(CompilerInstance &Compiler) override;
 
   /// \brief Returns true if the checker should suggest inserting a trailing
@@ -39,6 +52,9 @@
   /// \brief Get the canonical header guard for a file.
   virtual std::string getHeaderGuard(StringRef Filename,
                                      StringRef OldGuard = StringRef()) = 0;
+private:
+  utils::HeaderFileExtensionsSet HeaderFileExtensions;
+  std::string RawStringHeaderFileExtensions;
 };
 
 } // namespace utils
Index: clang-tidy/utils/HeaderGuard.cpp
===================================================================
--- clang-tidy/utils/HeaderGuard.cpp
+++ clang-tidy/utils/HeaderGuard.cpp
@@ -274,13 +274,13 @@
 }
 
 bool HeaderGuardCheck::shouldSuggestEndifComment(StringRef FileName) {
-  return FileName.endswith(".h");
+  return utils::isHeaderFileExtension(FileName, HeaderFileExtensions);
 }
 
 bool HeaderGuardCheck::shouldFixHeaderGuard(StringRef FileName) { return true; }
 
 bool HeaderGuardCheck::shouldSuggestToAddHeaderGuard(StringRef FileName) {
-  return FileName.endswith(".h");
+  return utils::isHeaderFileExtension(FileName, HeaderFileExtensions);
 }
 
 std::string HeaderGuardCheck::formatEndIf(StringRef HeaderGuard) {