diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 8533803ba6..11407ac902 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -1035,7 +1035,7 @@ class ForeignKey(ForeignObject):
         })
 
     def db_check(self, connection):
-        return []
+        return None
 
     def db_type(self, connection):
         return self.target_field.rel_db_type(connection=connection)