diff --git a/tox.ini b/tox.ini
index e5335e99..fadbda68 100644
--- a/tox.ini
+++ b/tox.ini
@@ -78,6 +78,7 @@ commands=
 [testenv:mypy]
 deps=
     typing_extensions
+    pydantic<2
     mypy
 commands=
     mypy tests/typing