diff --git a/packages/pubsub/src/subscription.js b/packages/pubsub/src/subscription.js
index e49f6479c3d..7d8e40b3ee7 100644
--- a/packages/pubsub/src/subscription.js
+++ b/packages/pubsub/src/subscription.js
@@ -409,6 +409,9 @@ Subscription.generateName_ = function() {
  * @throws {Error} If at least one ackId is not provided.
  *
  * @param {string|string[]} ackIds - An ackId or array of ackIds.
+ * @param {options=} options - Configuration object.
+ * @param {number} options.timeout - Set a maximum amount of time in
+ *     milliseconds before giving up if no response is received.
  * @param {function=} callback - The callback function.
  *
  * @example
@@ -423,7 +426,7 @@ Subscription.generateName_ = function() {
  *   var apiResponse = data[0];
  * });
  */
-Subscription.prototype.ack = function(ackIds, callback) {
+Subscription.prototype.ack = function(ackIds, options, callback) {
   var self = this;
 
   ackIds = arrify(ackIds);
@@ -434,6 +437,12 @@ Subscription.prototype.ack = function(ackIds, callback) {
     ].join(''));
   }
 
+  if (is.fn(options)) {
+    callback = options;
+    options = {};
+  }
+
+  options = options || {};
   callback = callback || common.util.noop;
 
   var protoOpts = {
@@ -441,6 +450,10 @@ Subscription.prototype.ack = function(ackIds, callback) {
     method: 'acknowledge'
   };
 
+  if (options && is.number(options.timeout)) {
+    protoOpts.timeout = options.timeout;
+  }
+
   var reqOpts = {
     subscription: this.name,
     ackIds: ackIds
diff --git a/packages/pubsub/test/subscription.js b/packages/pubsub/test/subscription.js
index 4f8002615bd..4f365cc4342 100644
--- a/packages/pubsub/test/subscription.js
+++ b/packages/pubsub/test/subscription.js
@@ -53,7 +53,8 @@ describe('Subscription', function() {
   var SUB_NAME = 'test-subscription';
   var SUB_FULL_NAME = 'projects/' + PROJECT_ID + '/subscriptions/' + SUB_NAME;
   var PUBSUB = {
-    projectId: PROJECT_ID
+    projectId: PROJECT_ID,
+    request: util.noop
   };
   var message = 'howdy';
   var messageBuffer = new Buffer(message).toString('base64');
@@ -410,6 +411,28 @@ describe('Subscription', function() {
       subscription.ack(IDS, assert.ifError);
     });
 
+    it('should honor the timeout setting', function(done) {
+      var options = {
+        timeout: 10
+      };
+
+      subscription.request = function(protoOpts) {
+        assert.strictEqual(protoOpts.timeout, options.timeout);
+        done();
+      };
+
+      subscription.ack('abc', options, assert.ifError);
+    });
+
+    it('should not require a callback', function() {
+      assert.doesNotThrow(function() {
+        subscription.ack('abc');
+        subscription.ack('abc', {
+          timeout: 10
+        });
+      });
+    });
+
     it('should unmark the ack ids as being in progress', function(done) {
       subscription.request = function(protoOpts, reqOpts, callback) {
         callback();