diff --git a/src/Responses/XmlAuthenticationSuccessResponse.php b/src/Responses/XmlAuthenticationSuccessResponse.php
index 2147758..3a1e3c5 100644
--- a/src/Responses/XmlAuthenticationSuccessResponse.php
+++ b/src/Responses/XmlAuthenticationSuccessResponse.php
@@ -49,9 +49,12 @@ public function setAttributes($attributes)
         $this->removeByXPath($authNode, 'cas:attributes');
         $attributesNode = $authNode->addChild('cas:attributes');
         foreach ($attributes as $key => $value) {
-            $str = $this->stringify($value);
-            if (is_string($str)) {
-                $attributesNode->addChild('cas:'.$key, $str);
+            $value_arr = (array) $value;
+            foreach($value_arr as $v){
+                $str = $this->stringify($v);
+                if (is_string($str)) {
+                    $attributesNode->addChild('cas:'.$key, $str);
+                }
             }
         }
 
diff --git a/tests/Responses/JsonAuthenticationSuccessResponseTest.php b/tests/Responses/JsonAuthenticationSuccessResponseTest.php
index 301efbe..c5ccb72 100644
--- a/tests/Responses/JsonAuthenticationSuccessResponseTest.php
+++ b/tests/Responses/JsonAuthenticationSuccessResponseTest.php
@@ -68,6 +68,15 @@ public function testSetAttributes()
         $this->assertEquals(['serviceResponse' => ['authenticationSuccess' => ['attributes' => $attr2]]], $data);
     }
 
+    public function testSetMultiValuedAttributes()
+    {
+        $resp  = new JsonAuthenticationSuccessResponse();
+        $attr1 = ['key1' => ['value1', 'value2']];
+        $resp->setAttributes($attr1);
+        $data = $this->getData($resp);
+        $this->assertEquals(['serviceResponse' => ['authenticationSuccess' => ['attributes' => $attr1]]], $data);
+    }
+
     protected function getData(JsonAuthenticationSuccessResponse $resp)
     {
         $property = self::getNonPublicProperty($resp, 'data');
diff --git a/tests/Responses/XmlAuthenticationSuccessResponseTest.php b/tests/Responses/XmlAuthenticationSuccessResponseTest.php
index 56612dc..0fb4b7e 100644
--- a/tests/Responses/XmlAuthenticationSuccessResponseTest.php
+++ b/tests/Responses/XmlAuthenticationSuccessResponseTest.php
@@ -54,12 +54,7 @@ public function testSetProxies()
 
     public function testSetAttributes()
     {
-        $resp    = Mockery::mock(XmlAuthenticationSuccessResponse::class, [])
-            ->makePartial()
-            ->shouldAllowMockingProtectedMethods()
-            ->shouldReceive('stringify')
-            ->andReturn('string')
-            ->getMock();
+        $resp    = new XmlAuthenticationSuccessResponse();
         $content = $this->getXML($resp);
         $this->assertNotContains('cas:attributes', $content);
 
@@ -76,6 +71,19 @@ public function testSetAttributes()
         $this->assertContains('cas:key3', $content);
     }
 
+    public function testSetMultiValuedAttributes()
+    {
+        $resp    = new XmlAuthenticationSuccessResponse();
+        $content = $this->getXML($resp);
+        $this->assertNotContains('cas:attributes', $content);
+
+        $resp->setAttributes(['key1' => ['value1', 'value2']]);
+        $content = $this->getXML($resp);
+        $this->assertContains('cas:attributes', $content);
+        $this->assertContains('<cas:key1>value1</cas:key1>', $content);
+        $this->assertContains('<cas:key1>value2</cas:key1>', $content);
+    }
+
     public function testSetProxyGrantingTicket()
     {
         $resp    = new XmlAuthenticationSuccessResponse();