diff --git a/src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php b/src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php
index 566d6a888773..a49099db0a7d 100644
--- a/src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php
+++ b/src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php
@@ -289,7 +289,7 @@ public function morphMany($related, $name, $type = null, $id = null, $localKey =
      * @param  string  $relation
      * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
      */
-    public function belongsToMany($related, $table = null, $foreignKey = null, $relatedKey = null, $relation = null)
+    public function belongsToMany($related, $table = null, $foreignKey = null, $relatedKey = null, $localKey = null, $relation = null)
     {
         // If no relationship name was passed, we will pull backtraces to get the
         // name of the calling function. We will use that function name as the
@@ -307,6 +307,8 @@ public function belongsToMany($related, $table = null, $foreignKey = null, $rela
 
         $relatedKey = $relatedKey ?: $instance->getForeignKey();
 
+        $localKey = $localKey ?: $this->getKeyName();
+
         // If no table name was provided, we can guess it by concatenating the two
         // models using underscores in alphabetical order. The two model names
         // are transformed to snake case from their default CamelCase also.
@@ -315,7 +317,7 @@ public function belongsToMany($related, $table = null, $foreignKey = null, $rela
         }
 
         return new BelongsToMany(
-            $instance->newQuery(), $this, $table, $foreignKey, $relatedKey, $relation
+            $instance->newQuery(), $this, $table, $foreignKey, $relatedKey, $localKey, $relation
         );
     }
 
diff --git a/src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php b/src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php
index 1c412433c63d..4af0325dfa37 100755
--- a/src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php
+++ b/src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php
@@ -101,12 +101,13 @@ class BelongsToMany extends Relation
      * @param  string  $relationName
      * @return void
      */
-    public function __construct(Builder $query, Model $parent, $table, $foreignKey, $relatedKey, $relationName = null)
+    public function __construct(Builder $query, Model $parent, $table, $foreignKey, $relatedKey, $localKey, $relationName = null)
     {
         $this->table = $table;
         $this->relatedKey = $relatedKey;
         $this->foreignKey = $foreignKey;
         $this->relationName = $relationName;
+        $this->localKey = $localKey;
 
         parent::__construct($query, $parent);
     }
@@ -140,7 +141,7 @@ protected function performJoin($query = null)
         // model instance. Then we can set the "where" for the parent models.
         $baseTable = $this->related->getTable();
 
-        $key = $baseTable.'.'.$this->related->getKeyName();
+        $key = $baseTable.'.'.$this->localKey;
 
         $query->join($this->table, $key, '=', $this->getQualifiedRelatedKeyName());
 
diff --git a/src/Illuminate/Database/Eloquent/Relations/MorphToMany.php b/src/Illuminate/Database/Eloquent/Relations/MorphToMany.php
index 0976ab6ac35d..1a6cfae3bfb5 100644
--- a/src/Illuminate/Database/Eloquent/Relations/MorphToMany.php
+++ b/src/Illuminate/Database/Eloquent/Relations/MorphToMany.php
@@ -44,13 +44,13 @@ class MorphToMany extends BelongsToMany
      * @param  bool  $inverse
      * @return void
      */
-    public function __construct(Builder $query, Model $parent, $name, $table, $foreignKey, $relatedKey, $relationName = null, $inverse = false)
+    public function __construct(Builder $query, Model $parent, $name, $table, $foreignKey, $relatedKey, $localKey, $relationName = null, $inverse = false)
     {
         $this->inverse = $inverse;
         $this->morphType = $name.'_type';
         $this->morphClass = $inverse ? $query->getModel()->getMorphClass() : $parent->getMorphClass();
 
-        parent::__construct($query, $parent, $table, $foreignKey, $relatedKey, $relationName);
+        parent::__construct($query, $parent, $table, $foreignKey, $relatedKey, $localKey, $relationName);
     }
 
     /**
diff --git a/tests/Database/DatabaseEloquentBelongsToManyTest.php b/tests/Database/DatabaseEloquentBelongsToManyTest.php
index 6c98b4e9d3dd..f1b1a77f231d 100755
--- a/tests/Database/DatabaseEloquentBelongsToManyTest.php
+++ b/tests/Database/DatabaseEloquentBelongsToManyTest.php
@@ -703,7 +703,7 @@ public function getRelation()
     {
         list($builder, $parent) = $this->getRelationArguments();
 
-        return new BelongsToMany($builder, $parent, 'user_role', 'user_id', 'role_id', 'relation_name');
+        return new BelongsToMany($builder, $parent, 'user_role', 'user_id', 'role_id', 'id', 'relation_name');
     }
 
     public function getRelationArguments()
@@ -728,7 +728,7 @@ public function getRelationArguments()
         $builder->shouldReceive('join')->once()->with('user_role', 'roles.id', '=', 'user_role.role_id');
         $builder->shouldReceive('where')->once()->with('user_role.user_id', '=', 1);
 
-        return [$builder, $parent, 'user_role', 'user_id', 'role_id', 'relation_name'];
+        return [$builder, $parent, 'user_role', 'user_id', 'role_id', 'id', 'relation_name'];
     }
 }
 
diff --git a/tests/Database/DatabaseEloquentMorphToManyTest.php b/tests/Database/DatabaseEloquentMorphToManyTest.php
index 1710011a6183..6e6077b7e0f0 100644
--- a/tests/Database/DatabaseEloquentMorphToManyTest.php
+++ b/tests/Database/DatabaseEloquentMorphToManyTest.php
@@ -74,7 +74,7 @@ public function getRelation()
     {
         list($builder, $parent) = $this->getRelationArguments();
 
-        return new MorphToMany($builder, $parent, 'taggable', 'taggables', 'taggable_id', 'tag_id');
+        return new MorphToMany($builder, $parent, 'taggable', 'taggables', 'taggable_id', 'tag_id', 'id');
     }
 
     public function getRelationArguments()
@@ -98,7 +98,7 @@ public function getRelationArguments()
         $builder->shouldReceive('where')->once()->with('taggables.taggable_id', '=', 1);
         $builder->shouldReceive('where')->once()->with('taggables.taggable_type', get_class($parent));
 
-        return [$builder, $parent, 'taggable', 'taggables', 'taggable_id', 'tag_id', 'relation_name', false];
+        return [$builder, $parent, 'taggable', 'taggables', 'taggable_id', 'tag_id', 'id', 'relation_name', false];
     }
 }