diff --git a/appengine/flexible/twilio/main.py b/appengine/flexible/twilio/main.py
index e3fe8edd51a..4f1049fb558 100644
--- a/appengine/flexible/twilio/main.py
+++ b/appengine/flexible/twilio/main.py
@@ -17,8 +17,8 @@
 import os
 
 from flask import Flask, request
-from twilio import twiml
-from twilio.rest import TwilioRestClient
+from twilio import rest
+from twilio.twiml import messaging_response, voice_response
 
 
 # [START configuration]
@@ -35,7 +35,7 @@
 @app.route('/call/receive', methods=['POST'])
 def receive_call():
     """Answers a call and replies with a simple greeting."""
-    response = twiml.Response()
+    response = voice_response.VoiceResponse()
     response.say('Hello from Twilio!')
     return str(response), 200, {'Content-Type': 'application/xml'}
 # [END receive_call]
@@ -50,11 +50,12 @@ def send_sms():
         return ('Please provide the number to message in the "to" query string'
                 ' parameter.'), 400
 
-    client = TwilioRestClient(TWILIO_ACCOUNT_SID, TWILIO_AUTH_TOKEN)
+    client = rest.Client(TWILIO_ACCOUNT_SID, TWILIO_AUTH_TOKEN)
     rv = client.messages.create(
         to=to,
         from_=TWILIO_NUMBER,
-        body='Hello from Twilio!')
+        body='Hello from Twilio!'
+    )
     return str(rv)
 # [END send_sms]
 
@@ -68,7 +69,7 @@ def receive_sms():
 
     message = 'Hello, {}, you said: {}'.format(sender, body)
 
-    response = twiml.Response()
+    response = messaging_response.MessagingResponse()
     response.message(message)
     return str(response), 200, {'Content-Type': 'application/xml'}
 # [END receive_sms]
diff --git a/appengine/flexible/twilio/main_test.py b/appengine/flexible/twilio/main_test.py
index b57c52d0d48..bfa037e2094 100644
--- a/appengine/flexible/twilio/main_test.py
+++ b/appengine/flexible/twilio/main_test.py
@@ -11,17 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import re
 
-import json
-
-from googleapiclient.http import HttpMockSequence
-import httplib2
 import pytest
-
-
-class HttpMockSequenceWithCredentials(HttpMockSequence):
-    def add_credentials(self, *args):
-        pass
+import responses
 
 
 @pytest.fixture
@@ -41,17 +34,34 @@ def test_receive_call(app):
     assert 'Hello from Twilio!' in r.data.decode('utf-8')
 
 
+@responses.activate
 def test_send_sms(app, monkeypatch):
-    httpmock = HttpMockSequenceWithCredentials([
-        ({'status': '200'}, json.dumps({
-            'sid': 'sid123'
-        }))
-    ])
-
-    def mock_http_ctor(*args, **kwargs):
-        return httpmock
-
-    monkeypatch.setattr(httplib2, 'Http', mock_http_ctor)
+    sample_response = {
+        "sid": "sid",
+        "date_created": "Wed, 20 Dec 2017 19:32:14 +0000",
+        "date_updated": "Wed, 20 Dec 2017 19:32:14 +0000",
+        "date_sent": None,
+        "account_sid": "account_sid",
+        "to": "+1234567890",
+        "from": "+9876543210",
+        "messaging_service_sid": None,
+        "body": "Hello from Twilio!",
+        "status": "queued",
+        "num_segments": "1",
+        "num_media": "0",
+        "direction": "outbound-api",
+        "api_version": "2010-04-01",
+        "price": None,
+        "price_unit": "USD",
+        "error_code": None,
+        "error_message": None,
+        "uri": "/2010-04-01/Accounts/sample.json",
+        "subresource_uris": {
+            "media": "/2010-04-01/Accounts/sample/Media.json"
+        }
+    }
+    responses.add(responses.POST, re.compile('.*'),
+                  json=sample_response, status=200)
 
     r = app.get('/sms/send')
     assert r.status_code == 400
diff --git a/appengine/flexible/twilio/requirements.txt b/appengine/flexible/twilio/requirements.txt
index dda690ab2e6..31c9947593a 100644
--- a/appengine/flexible/twilio/requirements.txt
+++ b/appengine/flexible/twilio/requirements.txt
@@ -1,3 +1,3 @@
 Flask==0.12.2
 gunicorn==19.7.1
-twilio<=6.0.0dev,==5.4.0
+twilio==6.10.0