diff --git a/clang-tools-extra/clang-tidy/llvm/IncludeOrderCheck.cpp b/clang-tools-extra/clang-tidy/llvm/IncludeOrderCheck.cpp
--- a/clang-tools-extra/clang-tidy/llvm/IncludeOrderCheck.cpp
+++ b/clang-tools-extra/clang-tidy/llvm/IncludeOrderCheck.cpp
@@ -67,7 +67,8 @@
     return 2;
 
   // System headers are sorted to the end.
-  if (IsAngled || Filename.startswith("gtest/"))
+  if (IsAngled || Filename.startswith("gtest/") ||
+      Filename.startswith("gmock/"))
     return 3;
 
   // Other headers are inserted between the main module header and LLVM headers.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/gmock/foo.h b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/gmock/foo.h
new file mode 100644
diff --git a/clang-tools-extra/test/clang-tidy/checkers/llvm-include-order.cpp b/clang-tools-extra/test/clang-tidy/checkers/llvm-include-order.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/llvm-include-order.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/llvm-include-order.cpp
@@ -3,6 +3,7 @@
 // CHECK-MESSAGES: [[@LINE+2]]:1: warning: #includes are not sorted properly
 #include "j.h"
 #include "gtest/foo.h"
+#include "gmock/foo.h"
 #include "i.h"
 #include <s.h>
 #include "llvm/a.h"
@@ -16,6 +17,7 @@
 // CHECK-FIXES-NEXT: #include "clang/b.h"
 // CHECK-FIXES-NEXT: #include "llvm-c/d.h" // -c
 // CHECK-FIXES-NEXT: #include "llvm/a.h"
+// CHECK-FIXES-NEXT: #include "gmock/foo.h"
 // CHECK-FIXES-NEXT: #include "gtest/foo.h"
 // CHECK-FIXES-NEXT: #include <s.h>