diff --git a/src/Illuminate/Database/Eloquent/Model.php b/src/Illuminate/Database/Eloquent/Model.php
index 846eb9490f24..54235ebd84fe 100644
--- a/src/Illuminate/Database/Eloquent/Model.php
+++ b/src/Illuminate/Database/Eloquent/Model.php
@@ -2063,7 +2063,7 @@ public function setPerPage($perPage)
      */
     public function getForeignKey()
     {
-        return Str::snake(class_basename($this)).'_id';
+        return Str::snake(class_basename($this)).'_'.$this->primaryKey;
     }
 
     /**