diff --git a/reclient_helper.py b/reclient_helper.py
index 44614e77c..108343df1 100644
--- a/reclient_helper.py
+++ b/reclient_helper.py
@@ -137,7 +137,7 @@ def set_reproxy_path_flags(out_dir, make_dirs=True):
     # unix domain socket has path length limit, so use fixed size path here.
     # ref: https://www.man7.org/linux/man-pages/man7/unix.7.html
     os.environ.setdefault(
-        "RBE_server_address", "unix://tmp/reproxy_%s.sock" %
+        "RBE_server_address", "unix:///tmp/reproxy_%s.sock" %
         hashlib.sha256(tmp_dir.encode()).hexdigest())
 
 
diff --git a/tests/ninja_reclient_test.py b/tests/ninja_reclient_test.py
index a2680600b..78f131ce3 100755
--- a/tests/ninja_reclient_test.py
+++ b/tests/ninja_reclient_test.py
@@ -87,7 +87,7 @@ class NinjaReclientTest(trial_dir.TestCase):
     else:
       self.assertEqual(
           os.environ.get('RBE_server_address'),
-          "unix://tmp/reproxy_%s.sock" % hashlib.sha256(
+          "unix:///tmp/reproxy_%s.sock" % hashlib.sha256(
               os.path.join(self.root_dir, "out", "a",
                            ".reproxy_tmp").encode()).hexdigest())