diff --git a/tools/clang-tidy-plugin/HeaderGuardCheck.cpp b/tools/clang-tidy-plugin/HeaderGuardCheck.cpp
index e967763aa85e4..d8090dd09c6ca 100644
--- a/tools/clang-tidy-plugin/HeaderGuardCheck.cpp
+++ b/tools/clang-tidy-plugin/HeaderGuardCheck.cpp
@@ -62,6 +62,7 @@ static std::string getHeaderGuard( StringRef Filename )
     Guard = Guard.substr( TopDir.length() + 1 );
 
     std::replace( Guard.begin(), Guard.end(), '/', '_' );
+    std::replace( Guard.begin(), Guard.end(), '\\', '_' );
     std::replace( Guard.begin(), Guard.end(), '.', '_' );
     std::replace( Guard.begin(), Guard.end(), '-', '_' );