diff --git a/clang-tools-extra/clang-tidy/utils/HeaderGuard.cpp b/clang-tools-extra/clang-tidy/utils/HeaderGuard.cpp
--- a/clang-tools-extra/clang-tidy/utils/HeaderGuard.cpp
+++ b/clang-tools-extra/clang-tidy/utils/HeaderGuard.cpp
@@ -145,13 +145,13 @@
         EndIfStr[FindEscapedNewline] == '\\')
       return false;
 
-    if (!Check->shouldSuggestEndifComment(FileName) &&
-        !(EndIfStr.startswith("//") ||
-          (EndIfStr.startswith("/*") && EndIfStr.endswith("*/"))))
-      return false;
+    bool IsLineComment =
+        EndIfStr.consume_front("//") ||
+        (EndIfStr.consume_front("/*") && EndIfStr.consume_back("*/"));
+    if (!IsLineComment)
+      return Check->shouldSuggestEndifComment(FileName);
 
-    return (EndIfStr != "// " + HeaderGuard.str()) &&
-           (EndIfStr != "/* " + HeaderGuard.str() + " */");
+    return EndIfStr.trim() != HeaderGuard;
   }
 
   /// Look for header guards that don't match the preferred style. Emit
diff --git a/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp b/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp
--- a/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp
+++ b/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp
@@ -204,6 +204,14 @@
                 "include/llvm/ADT/foo.h",
                 StringRef("header guard does not follow preferred style")));
 
+  // An extra space inside the comment is OK.
+  llvm::StringRef WithExtraSpace = "#ifndef LLVM_ADT_FOO_H\n"
+                                   "#define LLVM_ADT_FOO_H\n"
+                                   "#endif //  LLVM_ADT_FOO_H\n";
+  EXPECT_EQ(WithExtraSpace,
+            runHeaderGuardCheckWithEndif(WithExtraSpace,
+                                         "include/llvm/ADT/foo.h", None));
+
   EXPECT_EQ("#ifndef LLVM_ADT_FOO_H\n"
             "#define LLVM_ADT_FOO_H\n"
             "#endif \\ \n"