diff --git a/pyproject.toml b/pyproject.toml
index 64f665d0b..0b3fa17dc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,7 +28,7 @@ dependencies = [
   "gitpython ~= 3.0",
   "requests ~= 2.25",
   "jinja2 ~= 3.1",
-  "python-gitlab ~= 4.0",
+  "python-gitlab >= 4.0.0, < 6.0.0",
   "tomlkit ~= 0.11",
   "dotty-dict ~= 1.3",
   "importlib-resources ~= 6.0",