diff --git a/pyproject.toml b/pyproject.toml
index 1b99517f..cfac215e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -63,7 +63,7 @@ dev = [
   "coverage[toml]",
   "bandit",
   # "interrogate >= 1.7.0",
-  "mypy ~= 1.1",
+  "mypy >= 1.1,< 3.0",
   # NOTE(ww): ruff is under active development, so we pin conservatively here
   # and let Dependabot periodically perform this update.
   "ruff < 0.15.13",