diff --git a/noxfile.py b/noxfile.py
index d497f5305..498b66def 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -30,7 +30,7 @@
     "grpcio",
 ]
 
-ASYNC_DEPENDENCIES = ["pytest-asyncio", "aioresponses"]
+ASYNC_DEPENDENCIES = ["pytest-asyncio", "aioresponses", "asynctest"]
 
 BLACK_VERSION = "black==19.3b0"
 BLACK_PATHS = [