diff --git a/requirements_test.txt b/requirements_test.txt
index 6c9878b4..cf22b9aa 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -6,6 +6,6 @@ flake8-commas==2.0.0
 flake8-comprehensions==3.2.2
 flake8-docstrings==1.5.0
 flake8-quotes==3.2.0
-mypy==0.770
+mypy==0.991
 pydocstyle==5.0.2
 retrying==1.3.3