diff --git a/pyproject.toml b/pyproject.toml
index cb2530a5a..74cc3650e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -121,7 +121,7 @@ packages = ["/cosmos"]
 [tool.hatch.envs.tests]
 dependencies = [
     "astronomer-cosmos[tests]",
-    "apache-airflow-providers-postgres",
+    "apache-airflow-providers-postgres==5.11.0",
     "apache-airflow-providers-cncf-kubernetes>=5.1.1",
     "apache-airflow-providers-amazon>=3.0.0,<8.20.0", # https://github.com/apache/airflow/issues/39103
     "apache-airflow-providers-docker>=3.5.0",