diff --git a/BUILD.bazel b/BUILD.bazel
index 0e2e66edd2..f8815bbb8a 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -29,7 +29,6 @@ COPTS = [
     "-D__STDC_FORMAT_MACROS",
     "-D__STDC_LIMIT_MACROS",
     "-D__STDC_CONSTANT_MACROS",
-    "-DGFLAGS_NS=google",
 ] + select({
     "//bazel/config:brpc_with_glog": ["-DBRPC_WITH_GLOG=1"],
     "//conditions:default": ["-DBRPC_WITH_GLOG=0"],
@@ -104,6 +103,11 @@ genrule(
               "//conditions:default": "0",
           }) +
           """
+
+#ifndef GFLAGS_NS
+#define GFLAGS_NS google
+#endif
+
 #endif  // BUTIL_CONFIG_H
 EOF
     """,
diff --git a/config.h.in b/config.h.in
index 4f26e57775..b28fee4779 100644
--- a/config.h.in
+++ b/config.h.in
@@ -21,4 +21,8 @@
 #endif
 #cmakedefine BRPC_WITH_GLOG @WITH_GLOG_VAL@
 
+#ifndef GFLAGS_NS
+#define GFLAGS_NS google
+#endif
+
 #endif  // BUTIL_CONFIG_H
diff --git a/config_brpc.sh b/config_brpc.sh
index 2563b0e28e..5af2c67f50 100755
--- a/config_brpc.sh
+++ b/config_brpc.sh
@@ -493,7 +493,7 @@ fi
 append_to_output "CPPFLAGS=${CPPFLAGS}"
 append_to_output "# without the flag, linux+arm64 may crash due to folding on TLS.
 ifeq (\$(CC),gcc)
-  ifeq (\$(shell uname -p),aarch64) 
+  ifeq (\$(shell uname -p),aarch64)
     CPPFLAGS+=-fno-gcse
   endif
 endif
@@ -585,6 +585,10 @@ cat << EOF > src/butil/config.h
 #endif
 #define BRPC_WITH_GLOG $WITH_GLOG
 
+#ifndef GFLAGS_NS
+#define GFLAGS_NS google
+#endif
+
 #endif  // BUTIL_CONFIG_H
 EOF
 
diff --git a/example/BUILD.bazel b/example/BUILD.bazel
index afc525a331..b38cd5a156 100644
--- a/example/BUILD.bazel
+++ b/example/BUILD.bazel
@@ -28,7 +28,6 @@ COPTS = [
     "-fPIC",
     "-Wno-unused-parameter",
     "-fno-omit-frame-pointer",
-    "-DGFLAGS_NS=google",
 ] + select({
     "//bazel/config:brpc_with_glog": ["-DBRPC_WITH_GLOG=1"],
     "//conditions:default": ["-DBRPC_WITH_GLOG=0"],
diff --git a/test/BUILD.bazel b/test/BUILD.bazel
index 3c4242da22..9817b45f10 100644
--- a/test/BUILD.bazel
+++ b/test/BUILD.bazel
@@ -29,7 +29,6 @@ COPTS = [
     "-fPIC",
     "-Wno-unused-parameter",
     "-fno-omit-frame-pointer",
-    "-DGFLAGS_NS=google",
     "-fno-access-control",
     "-DBAZEL_TEST=1",
     "-DBVAR_NOT_LINK_DEFAULT_VARIABLES",