diff --git a/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp b/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp
index 5f7c1cd..4e70754 100644
--- a/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp
@@ -20,6 +20,24 @@
 namespace google {
 namespace readability {
 
+GlobalNamesInHeadersCheck::GlobalNamesInHeadersCheck(StringRef Name,
+                                                     ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      RawStringHeaderFileExtensions(
+          Options.getLocalOrGlobal("HeaderFileExtensions", "h")) {
+  if (!utils::parseHeaderFileExtensions(RawStringHeaderFileExtensions,
+                                        HeaderFileExtensions,
+                                        ',')) {
+    llvm::errs() << "Invalid header file extension: "
+                 << RawStringHeaderFileExtensions << "\n";
+  }
+}
+
+void GlobalNamesInHeadersCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "HeaderFileExtensions", RawStringHeaderFileExtensions);
+}
+
 void
 GlobalNamesInHeadersCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
   Finder->addMatcher(
@@ -38,10 +56,8 @@
   if (Result.SourceManager->isInMainFile(
           Result.SourceManager->getExpansionLoc(D->getLocStart()))) {
     // unless that file is a header.
-    StringRef Filename = Result.SourceManager->getFilename(
-        Result.SourceManager->getSpellingLoc(D->getLocStart()));
-
-    if (!Filename.endswith(".h"))
+    if (!utils::isSpellingLocInHeaderFile(
+            D->getLocStart(), *Result.SourceManager, HeaderFileExtensions))
       return;
   }
 
diff --git a/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.h b/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.h
index 07a380f..1320b49 100644
--- a/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.h
+++ b/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.h
@@ -11,20 +11,32 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_GLOBALNAMESINHEADERSCHECK_H
 
 #include "../ClangTidy.h"
+#include "../utils/HeaderFileExtensionsUtils.h"
 
 namespace clang {
 namespace tidy {
 namespace google {
 namespace readability {
 
-// Flag global namespace pollution in header files.
-// Right now it only triggers on using declarations and directives.
+/// Flag global namespace pollution in header files.
+/// Right now it only triggers on using declarations and directives.
+///
+/// The check supports these options:
+///   - `HeaderFileExtensions`: a comma-separated list of filename extensions
+///     of header files (The filename extensions should not contain "." prefix).
+///     "h" by default.
+///     For extension-less header files, using an empty string or leaving an
+///     empty string between "," if there are other filename extensions.
 class GlobalNamesInHeadersCheck : public ClangTidyCheck {
 public:
-  GlobalNamesInHeadersCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  GlobalNamesInHeadersCheck(StringRef Name, ClangTidyContext *Context);
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  const std::string RawStringHeaderFileExtensions;
+  utils::HeaderFileExtensionsSet HeaderFileExtensions;
 };
 
 } // namespace readability
diff --git a/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.cpp b/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.cpp
index 7ce245e..cf539ca 100644
--- a/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.cpp
@@ -19,6 +19,24 @@
 namespace google {
 namespace build {
 
+UnnamedNamespaceInHeaderCheck::UnnamedNamespaceInHeaderCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      RawStringHeaderFileExtensions(
+          Options.getLocalOrGlobal("HeaderFileExtensions", "h,hh,hpp,hxx")) {
+  if (!utils::parseHeaderFileExtensions(RawStringHeaderFileExtensions,
+                                        HeaderFileExtensions,
+                                        ',')) {
+    llvm::errs() << "Invalid header file extension: "
+                 << RawStringHeaderFileExtensions << "\n";
+  }
+}
+
+void UnnamedNamespaceInHeaderCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "HeaderFileExtensions", RawStringHeaderFileExtensions);
+}
+
 void UnnamedNamespaceInHeaderCheck::registerMatchers(
     ast_matchers::MatchFinder *Finder) {
   // Only register the matchers for C++; the functionality currently does not
@@ -30,17 +48,13 @@
 
 void
 UnnamedNamespaceInHeaderCheck::check(const MatchFinder::MatchResult &Result) {
-  SourceManager *SM = Result.SourceManager;
   const auto *N = Result.Nodes.getNodeAs<NamespaceDecl>("anonymousNamespace");
   SourceLocation Loc = N->getLocStart();
   if (!Loc.isValid())
     return;
 
-  // Look if we're inside a header, check for common suffixes only.
-  // TODO: Allow configuring the set of file extensions.
-  StringRef FileName = SM->getPresumedLoc(Loc).getFilename();
-  if (FileName.endswith(".h") || FileName.endswith(".hh") ||
-      FileName.endswith(".hpp") || FileName.endswith(".hxx"))
+  if (utils::isPresumedLocInHeaderFile(Loc, *Result.SourceManager,
+                                       HeaderFileExtensions))
     diag(Loc, "do not use unnamed namespaces in header files");
 }
 
diff --git a/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.h b/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.h
index 1d24943..fec1365 100644
--- a/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.h
+++ b/clang-tools-extra/clang-tidy/google/UnnamedNamespaceInHeaderCheck.h
@@ -11,6 +11,7 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_UNNAMEDNAMESPACEINHEADERCHECK_H
 
 #include "../ClangTidy.h"
+#include "../utils/HeaderFileExtensionsUtils.h"
 
 namespace clang {
 namespace tidy {
@@ -19,15 +20,26 @@
 
 /// Finds anonymous namespaces in headers.
 ///
+/// The check supports these options:
+///   - `HeaderFileExtensions`: a comma-separated list of filename extensions of
+///     header files (The filename extensions 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.
+///
 /// http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Namespaces#Namespaces
 ///
 /// Corresponding cpplint.py check name: 'build/namespaces'.
 class UnnamedNamespaceInHeaderCheck : public ClangTidyCheck {
 public:
-  UnnamedNamespaceInHeaderCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  UnnamedNamespaceInHeaderCheck(StringRef Name, ClangTidyContext *Context);
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  const std::string RawStringHeaderFileExtensions;
+  utils::HeaderFileExtensionsSet HeaderFileExtensions;
 };
 
 } // namespace build