diff --git a/setup.py b/setup.py
index 212c0c1..d835d6e 100644
--- a/setup.py
+++ b/setup.py
@@ -16,7 +16,7 @@
     license="MIT",
     py_modules=["pytest_timeout"],
     entry_points={"pytest11": ["timeout = pytest_timeout"]},
-    install_requires=["pytest>=5.0.0"],
+    install_requires=["pytest>=5.0.0", "py>=1.8.2"],
     python_requires=">=3.6",
     classifiers=[
         "Development Status :: 5 - Production/Stable",