diff --git a/src/Model.php b/src/Model.php
index a684e7d..1ae2b91 100644
--- a/src/Model.php
+++ b/src/Model.php
@@ -909,7 +909,7 @@ public function offsetUnset($offset)
      */
     public function __isset($key)
     {
-        return (isset($this->attributes[$key]) || isset($this->relations[$key])) ||
+        return (isset($this->attributes[$key]) ||
                 ($this->hasGetMutator($key) && ! is_null($this->getAttributeValue($key)));
     }