diff --git a/pyproject.toml b/pyproject.toml
index 7a78b26ce..c3e48f889 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -151,6 +151,7 @@ init_typed = true
 warn_required_dynamic_aliases = true
 
 [tool.ruff]
+target-version = "py39"
 line-length = 120
 fix = true
 show-fixes = true