diff --git a/src/Message.php b/src/Message.php
index eb072df7..ab9c01e7 100644
--- a/src/Message.php
+++ b/src/Message.php
@@ -314,6 +314,10 @@ public function setSender($emailOrAddress, $name = null)
      */
     public function getSender()
     {
+        $headers = $this->getHeaders();
+        if (!$headers->has('sender')) {
+            return null;
+        }
         $header = $this->getHeaderByName('sender', __NAMESPACE__ . '\Header\Sender');
         return $header->getAddress();
     }