diff --git a/packages/google-api-core/google/api_core/grpc_helpers.py b/packages/google-api-core/google/api_core/grpc_helpers.py
index 30ba19c54f1a..9dcd92c1ca4b 100644
--- a/packages/google-api-core/google/api_core/grpc_helpers.py
+++ b/packages/google-api-core/google/api_core/grpc_helpers.py
@@ -375,6 +375,17 @@ def create_channel(
     if attempt_direct_path:
         target = _modify_target_for_direct_path(target)
 
+    if "options" in kwargs and isinstance(kwargs["options"], (list, tuple)):
+        opts = list(kwargs["options"])
+        if not any(
+            isinstance(opt, (list, tuple))
+            and len(opt) >= 2
+            and opt[0] == "grpc.max_metadata_size"
+            for opt in opts
+        ):
+            opts.append(("grpc.max_metadata_size", 32768))
+        kwargs["options"] = opts
+
     return grpc.secure_channel(
         target, composite_credentials, compression=compression, **kwargs
     )
diff --git a/packages/google-api-core/google/api_core/grpc_helpers_async.py b/packages/google-api-core/google/api_core/grpc_helpers_async.py
index 780788e4b565..7ea91b307924 100644
--- a/packages/google-api-core/google/api_core/grpc_helpers_async.py
+++ b/packages/google-api-core/google/api_core/grpc_helpers_async.py
@@ -304,6 +304,17 @@ def create_channel(
     if attempt_direct_path:
         target = grpc_helpers._modify_target_for_direct_path(target)
 
+    if "options" in kwargs and isinstance(kwargs["options"], (list, tuple)):
+        opts = list(kwargs["options"])
+        if not any(
+            isinstance(opt, (list, tuple))
+            and len(opt) >= 2
+            and opt[0] == "grpc.max_metadata_size"
+            for opt in opts
+        ):
+            opts.append(("grpc.max_metadata_size", 32768))
+        kwargs["options"] = opts
+
     return aio.secure_channel(
         target, composite_credentials, compression=compression, **kwargs
     )
diff --git a/packages/google-api-core/tests/asyncio/test_grpc_helpers_async.py b/packages/google-api-core/tests/asyncio/test_grpc_helpers_async.py
index 43700f22bc83..65f3693ccbc2 100644
--- a/packages/google-api-core/tests/asyncio/test_grpc_helpers_async.py
+++ b/packages/google-api-core/tests/asyncio/test_grpc_helpers_async.py
@@ -730,6 +730,15 @@ def test_create_channel(grpc_secure_channel):
     credentials.with_scopes.assert_called_once_with(scopes, default_scopes=None)
 
 
+@mock.patch("google.auth.default", return_value=(mock.sentinel.credentials, None))
+@mock.patch("grpc.aio.secure_channel")
+def test_create_channel_max_metadata_size(grpc_secure_channel, auth_default):
+    options = [("grpc.max_send_message_length", -1)]
+    grpc_helpers_async.create_channel("example.com:443", options=options)
+    _, kwargs = grpc_secure_channel.call_args
+    assert ("grpc.max_metadata_size", 32768) in kwargs["options"]
+
+
 @pytest.mark.asyncio
 async def test_fake_stream_unary_call():
     fake_call = grpc_helpers_async.FakeStreamUnaryCall()
diff --git a/packages/google-api-core/tests/unit/test_grpc_helpers.py b/packages/google-api-core/tests/unit/test_grpc_helpers.py
index e05d3969951f..edf865dac685 100644
--- a/packages/google-api-core/tests/unit/test_grpc_helpers.py
+++ b/packages/google-api-core/tests/unit/test_grpc_helpers.py
@@ -925,3 +925,12 @@ def test_subscribe_unsubscribe(self):
     def test_close(self):
         channel = grpc_helpers.ChannelStub()
         assert channel.close() is None
+
+
+@mock.patch("google.auth.default", return_value=(mock.sentinel.credentials, None))
+@mock.patch("grpc.secure_channel")
+def test_create_channel_max_metadata_size(grpc_secure_channel, auth_default):
+    options = [("grpc.max_send_message_length", -1)]
+    grpc_helpers.create_channel("example.com:443", options=options)
+    _, kwargs = grpc_secure_channel.call_args
+    assert ("grpc.max_metadata_size", 32768) in kwargs["options"]