diff --git a/src/Adapter/Callback.php b/src/Adapter/Callback.php
new file mode 100644
index 0000000..dd39956
--- /dev/null
+++ b/src/Adapter/Callback.php
@@ -0,0 +1,90 @@
+<?php
+/**
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link      http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace Zend\Authentication\Adapter;
+
+use Exception;
+use Zend\Authentication\Exception\InvalidArgumentException;
+use Zend\Authentication\Exception\RuntimeException;
+use Zend\Authentication\Result;
+
+/**
+ * Authentication Adapter authenticates using callback function.
+ *
+ * The Callback function must return an identity on authentication success,
+ * and false on authentication failure.
+ */
+class Callback extends AbstractAdapter
+{
+    /**
+     * @var callable
+     */
+    protected $callback;
+
+    /**
+     * @param callable $callback The authentication callback
+     */
+    public function __construct($callback = null)
+    {
+        if (null !== $callback) {
+            $this->setCallback($callback);
+        }
+    }
+
+    /**
+     * Authenticate using the provided callback
+     *
+     * @return Result The authentication result
+     * @throws RuntimeException
+     */
+    public function authenticate()
+    {
+        $callback = $this->getCallback();
+        if (! $callback) {
+            throw new RuntimeException('No callback provided');
+        }
+
+        try {
+            $identity = call_user_func($callback, $this->getIdentity(), $this->getCredential());
+        } catch (Exception $e) {
+            return new Result(Result::FAILURE_UNCATEGORIZED, null, array($e->getMessage()));
+        }
+
+        if (! $identity) {
+            return new Result(Result::FAILURE, null, array('Authentication failure'));
+        }
+
+        return new Result(Result::SUCCESS, $identity, array('Authentication success'));
+    }
+
+    /**
+     * Gets the value of callback.
+     *
+     * @return null|callable
+     */
+    public function getCallback()
+    {
+        return $this->callback;
+    }
+
+    /**
+     * Sets the value of callback.
+     *
+     * @param  callable $callback the callback
+     * @throws InvalidArgumentException
+     */
+    public function setCallback($callback)
+    {
+        if (! is_callable($callback)) {
+            throw new InvalidArgumentException('Invalid callback provided');
+        }
+
+        $this->callback = $callback;
+    }
+}
diff --git a/test/Adapter/CallbackTest.php b/test/Adapter/CallbackTest.php
new file mode 100644
index 0000000..a205dc0
--- /dev/null
+++ b/test/Adapter/CallbackTest.php
@@ -0,0 +1,160 @@
+<?php
+/**
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link      http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace ZendTest\Authentication\Adapter;
+
+use Exception;
+use PHPUnit_Framework_TestCase as TestCase;
+use Zend\Authentication\Adapter\Callback;
+use Zend\Authentication\Result;
+
+class CallbackTest extends TestCase
+{
+    /**
+     * Callback authentication adapter
+     *
+     * @var Callback
+     */
+    protected $adapter = null;
+
+    /**
+     * Set up test configuration
+     */
+    public function setUp()
+    {
+        $this->setupAuthAdapter();
+    }
+
+    public function tearDown()
+    {
+        $this->adapter = null;
+    }
+
+    protected function setupAuthAdapter()
+    {
+        $this->adapter = new Callback();
+    }
+
+    /**
+     * Ensures expected behavior for an invalid callback
+     */
+    public function testSetCallbackThrowsException()
+    {
+        $this->setExpectedException(
+            'Zend\Authentication\Exception\InvalidArgumentException',
+            'Invalid callback provided'
+        );
+        $this->adapter->setCallback('This is not a valid callback');
+    }
+
+    /**
+     * Ensures setter/getter behaviour for callback
+     */
+    public function testCallbackSetGetMethods()
+    {
+        $callback = function () {
+        };
+        $this->adapter->setCallback($callback);
+        $this->assertEquals($callback, $this->adapter->getCallback());
+    }
+
+    /**
+     * Ensures constructor sets callback if provided
+     */
+    public function testClassConstructorSetCallback()
+    {
+        $callback = function () {
+        };
+        $adapter  = new Callback($callback);
+        $this->assertEquals($callback, $adapter->getCallback());
+    }
+
+    /**
+     * Ensures authenticate throws Exception if no callback is defined
+     */
+    public function testAuthenticateThrowsException()
+    {
+        $this->setExpectedException(
+            'Zend\Authentication\Exception\RuntimeException',
+            'No callback provided'
+        );
+        $this->adapter->authenticate();
+    }
+
+    /**
+     * Ensures identity and credential are provided as arguments to callback
+     */
+    public function testAuthenticateProvidesCallbackWithIdentityAndCredentials()
+    {
+        $adapter = $this->adapter;
+        $adapter->setIdentity('testIdentity');
+        $adapter->setCredential('testCredential');
+        $that = $this;
+        $callback = function ($identity, $credential) use ($that, $adapter) {
+            $that->assertEquals($identity, $adapter->getIdentity());
+            $that->assertEquals($credential, $adapter->getCredential());
+        };
+        $this->adapter->setCallback($callback);
+        $this->adapter->authenticate();
+    }
+
+    /**
+     * Ensures authentication result is invalid when callback throws exception
+     */
+    public function testAuthenticateResultIfCallbackThrows()
+    {
+        $adapter   = $this->adapter;
+        $exception = new Exception('Callback Exception');
+        $callback  = function () use ($exception) {
+            throw $exception;
+        };
+        $adapter->setCallback($callback);
+        $result = $adapter->authenticate();
+        $this->assertFalse($result->isValid());
+        $this->assertEquals(Result::FAILURE_UNCATEGORIZED, $result->getCode());
+        $this->assertEquals(array($exception->getMessage()), $result->getMessages());
+    }
+
+    /**
+     * Ensures authentication result is invalid when callback returns falsy value
+     */
+    public function testAuthenticateResultIfCallbackReturnsFalsy()
+    {
+        $that    = $this;
+        $adapter = $this->adapter;
+        $falsyValues = array(false, null, '', '0', array(), 0, 0.0);
+        array_map(function ($falsy) use ($that, $adapter) {
+            $callback = function () use ($falsy) {
+                return $falsy;
+            };
+            $adapter->setCallback($callback);
+            $result = $adapter->authenticate();
+            $that->assertFalse($result->isValid());
+            $that->assertEquals(Result::FAILURE, $result->getCode());
+            $that->assertEquals(array('Authentication failure'), $result->getMessages());
+        }, $falsyValues);
+    }
+
+    /**
+     * Ensures authentication result is valid when callback returns truthy value
+     */
+    public function testAuthenticateResultIfCallbackReturnsIdentity()
+    {
+        $adapter  = $this->adapter;
+        $callback = function () {
+            return 'identity';
+        };
+        $adapter->setCallback($callback);
+        $result = $adapter->authenticate();
+        $this->assertTrue($result->isValid());
+        $this->assertEquals(Result::SUCCESS, $result->getCode());
+        $this->assertEquals('identity', $result->getIdentity());
+        $this->assertEquals(array('Authentication success'), $result->getMessages());
+    }
+}