diff --git a/tox.ini b/tox.ini
index 093086e4..e1b2fcdb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ envlist=
 [testenv]
 deps=
     pytest
+    pytest-asyncio
     # TODO: Hotfix, remove when fixed https://github.com/aio-libs/aiohttp/issues/5107
     typing_extensions
     httpx
@@ -47,6 +48,7 @@ commands = pytest -c tests/.configs/pytest-py27.ini
 [testenv:3.5]
 deps=
     pytest
+    pytest-asyncio
     contextvars
 extras=
     yaml
@@ -64,6 +66,7 @@ commands = pytest -c tests/.configs/pytest-py27.ini
 [testenv:pypy3]
 deps=
     pytest
+    pytest-asyncio
     httpx
     fastapi
     boto3