diff --git a/src/iam.js b/src/iam.js
index fc6588ea1..829c4687d 100644
--- a/src/iam.js
+++ b/src/iam.js
@@ -63,6 +63,10 @@ var is = require('is');
  * // subscription.iam
  */
 function IAM(pubsub, id) {
+  if (pubsub.Promise) {
+    this.Promise = pubsub.Promise;
+  }
+
   this.pubsub = pubsub;
   this.request = pubsub.request.bind(pubsub);
   this.id = id;
diff --git a/src/index.js b/src/index.js
index ec84e038c..df3e6e5da 100644
--- a/src/index.js
+++ b/src/index.js
@@ -103,6 +103,10 @@ function PubSub(options) {
   this.api = {};
   this.auth = googleAuth(this.options);
   this.projectId = this.options.projectId || PROJECT_ID_PLACEHOLDER;
+
+  if (this.options.promise) {
+    this.Promise = this.options.promise;
+  }
 }
 
 /**
diff --git a/src/publisher.js b/src/publisher.js
index f1b9c5adf..d91f3add1 100644
--- a/src/publisher.js
+++ b/src/publisher.js
@@ -53,6 +53,10 @@ var is = require('is');
  * var publisher = topic.publisher();
  */
 function Publisher(topic, options) {
+  if (topic.Promise) {
+    this.Promise = topic.Promise;
+  }
+
   options = extend(
     true,
     {
diff --git a/src/snapshot.js b/src/snapshot.js
index dbb587b12..ee12d5030 100644
--- a/src/snapshot.js
+++ b/src/snapshot.js
@@ -89,6 +89,10 @@ var is = require('is');
  * });
  */
 function Snapshot(parent, name) {
+  if (parent.Promise) {
+    this.Promise = parent.Promise;
+  }
+
   this.parent = parent;
   this.name = Snapshot.formatName_(parent.projectId, name);
 
diff --git a/src/subscription.js b/src/subscription.js
index 3f1cd0f95..ab58fbf33 100644
--- a/src/subscription.js
+++ b/src/subscription.js
@@ -155,6 +155,10 @@ var Snapshot = require('./snapshot.js');
  * subscription.removeListener('message', onMessage);
  */
 function Subscription(pubsub, name, options) {
+  if (pubsub.Promise) {
+    this.Promise = pubsub.Promise;
+  }
+
   options = options || {};
 
   this.pubsub = pubsub;
diff --git a/src/topic.js b/src/topic.js
index 3a9f582b9..d16d7dc74 100644
--- a/src/topic.js
+++ b/src/topic.js
@@ -51,6 +51,10 @@ var Publisher = require('./publisher.js');
  * var topic = pubsub.topic('my-topic');
  */
 function Topic(pubsub, name) {
+  if (pubsub.Promise) {
+    this.Promise = pubsub.Promise;
+  }
+
   this.name = Topic.formatName_(pubsub.projectId, name);
   this.parent = this.pubsub = pubsub;
   this.request = pubsub.request.bind(pubsub);
diff --git a/test/iam.js b/test/iam.js
index 5631e79bd..6d93bbe8d 100644
--- a/test/iam.js
+++ b/test/iam.js
@@ -36,6 +36,7 @@ describe('IAM', function() {
 
   var PUBSUB = {
     options: {},
+    Promise: {},
     request: util.noop,
   };
   var ID = 'id';
@@ -53,6 +54,10 @@ describe('IAM', function() {
   });
 
   describe('initialization', function() {
+    it('should localize pubsub.Promise', function() {
+      assert.strictEqual(iam.Promise, PUBSUB.Promise);
+    });
+
     it('should localize pubsub', function() {
       assert.strictEqual(iam.pubsub, PUBSUB);
     });
diff --git a/test/index.js b/test/index.js
index f22487444..add40194a 100644
--- a/test/index.js
+++ b/test/index.js
@@ -109,7 +109,10 @@ describe('PubSub', function() {
   var PubSub;
   var PROJECT_ID = 'test-project';
   var pubsub;
-  var OPTIONS = {projectId: PROJECT_ID};
+  var OPTIONS = {
+    projectId: PROJECT_ID,
+    promise: {},
+  };
 
   var PUBSUB_EMULATOR_HOST = process.env.PUBSUB_EMULATOR_HOST;
 
@@ -261,6 +264,10 @@ describe('PubSub', function() {
     it('should set isEmulator to false by default', function() {
       assert.strictEqual(pubsub.isEmulator, false);
     });
+
+    it('should localize a Promise override', function() {
+      assert.strictEqual(pubsub.Promise, OPTIONS.promise);
+    });
   });
 
   describe('createSubscription', function() {
diff --git a/test/publisher.js b/test/publisher.js
index e0c130504..f4e1a9abd 100644
--- a/test/publisher.js
+++ b/test/publisher.js
@@ -39,6 +39,7 @@ describe('Publisher', function() {
   var TOPIC_NAME = 'test-topic';
   var TOPIC = {
     name: TOPIC_NAME,
+    Promise: {},
     request: fakeUtil.noop,
   };
 
@@ -61,6 +62,10 @@ describe('Publisher', function() {
       assert(promisified);
     });
 
+    it('should localize topic.Promise', function() {
+      assert.strictEqual(publisher.Promise, TOPIC.Promise);
+    });
+
     it('should localize the topic object', function() {
       assert.strictEqual(publisher.topic, TOPIC);
     });
diff --git a/test/snapshot.js b/test/snapshot.js
index b09b5a07e..cd0348209 100644
--- a/test/snapshot.js
+++ b/test/snapshot.js
@@ -42,8 +42,9 @@ describe('Snapshot', function() {
   };
 
   var SUBSCRIPTION = {
-    pubsub: PUBSUB,
+    Promise: {},
     projectId: PROJECT_ID,
+    pubsub: PUBSUB,
     api: {},
     createSnapshot: function() {},
     seek: function() {},
@@ -81,6 +82,10 @@ describe('Snapshot', function() {
       assert(promisified);
     });
 
+    it('should localize parent.Promise', function() {
+      assert.strictEqual(snapshot.Promise, SUBSCRIPTION.Promise);
+    });
+
     it('should localize the parent', function() {
       assert.strictEqual(snapshot.parent, SUBSCRIPTION);
     });
diff --git a/test/subscription.js b/test/subscription.js
index eed5773b9..f45e0246c 100644
--- a/test/subscription.js
+++ b/test/subscription.js
@@ -72,6 +72,7 @@ describe('Subscription', function() {
 
   var PUBSUB = {
     projectId: PROJECT_ID,
+    Promise: {},
     request: fakeUtil.noop,
   };
 
@@ -98,6 +99,10 @@ describe('Subscription', function() {
       assert(promisified);
     });
 
+    it('should localize pubsub.Promise', function() {
+      assert.strictEqual(subscription.Promise, PUBSUB.Promise);
+    });
+
     it('should localize the pubsub object', function() {
       assert.strictEqual(subscription.pubsub, PUBSUB);
     });
diff --git a/test/topic.js b/test/topic.js
index 9487f156a..4d3b865d5 100644
--- a/test/topic.js
+++ b/test/topic.js
@@ -65,6 +65,7 @@ describe('Topic', function() {
   var TOPIC_UNFORMATTED_NAME = TOPIC_NAME.split('/').pop();
 
   var PUBSUB = {
+    Promise: {},
     projectId: PROJECT_ID,
     createTopic: util.noop,
     request: util.noop,
@@ -99,6 +100,10 @@ describe('Topic', function() {
       assert(promisified);
     });
 
+    it('should localize pubsub.Promise', function() {
+      assert.strictEqual(topic.Promise, PUBSUB.Promise);
+    });
+
     it('should format the name', function() {
       var formattedName = 'a/b/c/d';