diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1eaccff..d2b3966 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,7 +35,7 @@ jobs:
         extensions: redis
 
     - name: Setup Redis
-      run: sudo apt install redis -y ; sudo systemctl stop redis\* ; redis-cli --version
+      run: sudo add-apt-repository ppa:redislabs/redis -y -u ; sudo apt install redis -y ; sudo systemctl stop redis\* ; redis-cli --version
 
     - name: Install phpunit
       env:
diff --git a/Client.php b/Client.php
index 72b209a..4a253da 100755
--- a/Client.php
+++ b/Client.php
@@ -273,6 +273,11 @@ class Credis_Client {
      */
     protected $isWatching = FALSE;
 
+    /**
+     * @var string
+     */
+    protected $authUsername;
+
     /**
      * @var string
      */
@@ -315,8 +320,9 @@ class Credis_Client {
      * @param string $persistent  Flag to establish persistent connection
      * @param int $db The selected datbase of the Redis server
      * @param string $password The authentication password of the Redis server
+     * @param string $username The authentication username of the Redis server
      */
-    public function __construct($host = '127.0.0.1', $port = 6379, $timeout = null, $persistent = '', $db = 0, $password = null)
+    public function __construct($host = '127.0.0.1', $port = 6379, $timeout = null, $persistent = '', $db = 0, $password = null, $username = null)
     {
         $this->host = (string) $host;
         $this->port = (int) $port;
@@ -325,10 +331,15 @@ public function __construct($host = '127.0.0.1', $port = 6379, $timeout = null,
         $this->persistent = (string) $persistent;
         $this->standalone = ! extension_loaded('redis');
         $this->authPassword = $password;
+        $this->authUsername = $username;
         $this->selectedDb = (int)$db;
         $this->convertHost();
-        // PHP Redis extension support TLS since 5.3.0
-        if ($this->scheme == 'tls' && !$this->standalone && version_compare(phpversion('redis'),'5.3.0','<')){
+        // PHP Redis extension support TLS/ACL AUTH since 5.3.0
+        if ((
+              $this->scheme === 'tls'
+              || $this->authUsername !== null
+            )
+            && !$this->standalone && version_compare(phpversion('redis'),'5.3.0','<')){
             $this->standalone = true;
         }
     }
@@ -504,9 +515,8 @@ public function connect()
         if ($this->readTimeout) {
             $this->setReadTimeout($this->readTimeout);
         }
-
         if($this->authPassword) {
-            $this->auth($this->authPassword);
+            $this->auth($this->authPassword, $this->authUsername);
         }
         if($this->selectedDb !== 0) {
             $this->select($this->selectedDb);
@@ -641,11 +651,17 @@ public function getRenamedCommand($command)
 
     /**
      * @param string $password
+     * @param string|null $username
      * @return bool
      */
-    public function auth($password)
+    public function auth($password, $username = null)
     {
-        $response = $this->__call('auth', array($password));
+        if ($username !== null) {
+            $response = $this->__call('auth', array($username, $password));
+            $this->authUsername= $username;
+        } else {
+            $response = $this->__call('auth', array($password));
+        }
         $this->authPassword = $password;
         return $response;
     }
@@ -1150,6 +1166,10 @@ public function __call($name, $args)
                     // allow phpredis to see the caller's reference
                     //$param_ref =& $args[0];
                     break;
+                case 'auth':
+                    // For phpredis pre-v5.3, the type signature is string, not array|string
+                    $args = (is_array($args) && count($args) === 1) ? $args : array($args);
+                    break;
                 default:
                     // Flatten arguments
                     $args = self::_flattenArguments($args);
@@ -1185,6 +1205,7 @@ public function __call($name, $args)
                     return $this;
                 }
 
+
                 // Send request, retry one time when using persistent connections on the first request only
                 $this->requests++;
                 try {
diff --git a/tests/CredisTest.php b/tests/CredisTest.php
index 3e1f392..6c0f38a 100644
--- a/tests/CredisTest.php
+++ b/tests/CredisTest.php
@@ -620,6 +620,73 @@ public function testPassword()
       $this->assertTrue($this->credis->set('key','value'));
   }
 
+  /**
+   * @group Auth
+   */
+  public function testUsernameAndPassword()
+  {
+      $this->tearDown();
+      $this->assertArrayHasKey('password',$this->redisConfig[7]);
+      $this->credis = new Credis_Client($this->redisConfig[7]['host'], $this->redisConfig[7]['port'], $this->redisConfig[7]['timeout'], false, 0, $this->redisConfig[7]['password'], $this->redisConfig[7]['username']);
+      if ($this->useStandalone) {
+          $this->credis->forceStandalone();
+      }
+      $this->assertInstanceOf('Credis_Client',$this->credis->connect());
+      $this->assertTrue($this->credis->set('key','value'));
+      $this->credis->close();
+      $this->credis = new Credis_Client($this->redisConfig[7]['host'], $this->redisConfig[7]['port'], $this->redisConfig[7]['timeout'], false, 0, 'wrongpassword', $this->redisConfig[7]['username']);
+      if ($this->useStandalone) {
+          $this->credis->forceStandalone();
+      }
+      try
+      {
+          $this->credis->connect();
+          $this->fail('connect should fail with wrong password');
+      }
+      catch(CredisException $e)
+      {
+          if (strpos($e->getMessage(), 'username') !== false)
+          {
+            $this->assertStringStartsWith('WRONGPASS invalid username-password pair', $e->getMessage());
+          }
+          else
+          {
+            $this->assertStringStartsWith('ERR invalid password', $e->getMessage());
+          }
+
+          $this->credis->close();
+      }
+      $this->credis = new Credis_Client($this->redisConfig[7]['host'], $this->redisConfig[7]['port'], $this->redisConfig[7]['timeout'], false, 0);
+      if ($this->useStandalone) {
+          $this->credis->forceStandalone();
+      }
+      try
+      {
+          $this->credis->set('key', 'value');
+      }
+      catch(CredisException $e)
+      {
+          $this->assertStringStartsWith('NOAUTH Authentication required', $e->getMessage());
+      }
+      try
+      {
+          $this->credis->auth('anotherwrongpassword');
+      }
+      catch(CredisException $e)
+      {
+        if (strpos($e->getMessage(), 'username') !== false)
+        {
+          $this->assertStringStartsWith('WRONGPASS invalid username-password pair', $e->getMessage());
+        }
+        else
+        {
+          $this->assertStringStartsWith('ERR invalid password', $e->getMessage());
+        }
+      }
+      $this->assertTrue($this->credis->auth('thepassword'));
+      $this->assertTrue($this->credis->set('key','value'));
+  }
+
   public function testGettersAndSetters()
   {
       $this->assertEquals($this->credis->getHost(),$this->redisConfig[0]['host']);
diff --git a/tests/redis_config.json b/tests/redis_config.json
index c696fb3..f153f34 100644
--- a/tests/redis_config.json
+++ b/tests/redis_config.json
@@ -5,5 +5,6 @@
     {"host":"127.0.0.1","port":6382,"timeout":2.5,"alias":"fourth"},
     {"host":"127.0.0.1","port":6383,"timeout":2.5,"alias":"auth", "password": "thepassword"},
     {"host":"127.0.0.1","port":6384,"timeout":2.5,"alias":"socket"},
-    {"host":"127.0.0.1","port":6385,"timeout":2.5,"alias":"slave"}
+    {"host":"127.0.0.1","port":6385,"timeout":2.5,"alias":"slave"},
+    {"host":"127.0.0.1","port":6383,"timeout":2.5,"alias":"userauth", "username": "default", "password": "thepassword"}
 ]
\ No newline at end of file