diff --git a/setup.py b/setup.py
index 9991e9ad..b57f7be2 100644
--- a/setup.py
+++ b/setup.py
@@ -49,6 +49,7 @@ tests_require = [
     "pytest-benchmark",
     "pytest-cov",
     "pytest-mock",
+    "pytest-asyncio",
     "snapshottest",
     "coveralls",
     "promise",
diff --git a/tox.ini b/tox.ini
index 6581d340..5529dc23 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,7 +5,6 @@ skipsdist = true
 [testenv]
 deps =
     .[test]
-    py{36,37}: pytest-asyncio
 setenv =
      PYTHONPATH = .:{envdir}
 commands =