diff --git a/tox.ini b/tox.ini
index e9dc394f..8d024bce 100644
--- a/tox.ini
+++ b/tox.ini
@@ -83,7 +83,7 @@ deps =
     ext-flask: flask >= 0.10
 
     ext-flask_sqlalchemy: flask >= 0.10
-    ext-flask_sqlalchemy: Flask-SQLAlchemy
+    ext-flask_sqlalchemy: Flask-SQLAlchemy <= 2.5.1
 
     ext-sqlalchemy: sqlalchemy