diff --git a/pyramid/scaffolds/alchemy/+package+/models/__init__.py b/pyramid/scaffolds/alchemy/+package+/models/__init__.py
index a6fe0d6eeb..6ffc10a78c 100644
--- a/pyramid/scaffolds/alchemy/+package+/models/__init__.py
+++ b/pyramid/scaffolds/alchemy/+package+/models/__init__.py
@@ -1,3 +1,7 @@
+from sqlalchemy.orm import configure_mappers
 # import all models classes here for sqlalchemy mappers
 # to pick up
 from .mymodel import MyModel # flake8: noqa
+
+# run configure mappers to ensure we avoid any race conditions
+configure_mappers()