diff --git a/.travis.yml b/.travis.yml
index 0db93a3b1..a5422a5d9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,10 +4,20 @@ php:
   - '5.6.25'
   - '7.0'
   - '7.1'
+env:
+  - PROTOBUF_C_EXT=true
+  - PROTOBUF_C_EXT=false
+matrix:
+  exclude:
+    - php: '5.5.38'
+      env: PROTOBUF_C_EXT=true
+    - php: '7.0'
+      env: PROTOBUF_C_EXT=true
 sudo: required
 dist: trusty
 install:
   - travis_retry pecl install grpc
+  - if [[ $PROTOBUF_C_EXT =~ ^true ]]; then travis_retry pecl install protobuf; fi
   - composer install
 script:
   - vendor/bin/phpunit --coverage-clover=coverage.xml
diff --git a/tests/ProtobufExtensionTest.php b/tests/ProtobufExtensionTest.php
new file mode 100644
index 000000000..c64cd13eb
--- /dev/null
+++ b/tests/ProtobufExtensionTest.php
@@ -0,0 +1,51 @@
+<?php
+/*
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+namespace Google\GAX\UnitTests;
+
+use PHPUnit_Framework_TestCase;
+
+class ProtobufExtensionTest extends PHPUnit_Framework_TestCase
+{
+    public function setUp()
+    {
+        if (!extension_loaded('protobuf')) {
+            $this->markTestSkipped('Must have the protobuf extension installed to run this test.');
+        }
+    }
+
+    public function testForProtobufExtension()
+    {
+        // This test should always pass - we have it here so that we can determine whether the
+        // protobuf extension is installed, based on whether this test passes or is skipped
+        $this->assertTrue(true);
+    }
+}