diff --git a/.circleci/config.yml b/.circleci/config.yml
index 29ef519..b201a55 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,11 +7,21 @@ jobs:
             - image: circleci/python:3.7
         steps:
             - checkout
+
+            # Install Tox.
+            - restore_cache:
+                key: dep
             - run:
                 command: sudo pip install tox
+            - save_cache:
+                key: dep
+                paths:
+                    - "/usr/local/bin"
+                    - "/usr/local/lib/python3.7/site-packages"
+
+            # Run Tox.
             - restore_cache:
                 key: tox-{{ checksum "tox.ini" }}
-                paths: [".tox"]
             - run:
                 command: tox -e py37,flake8
             - save_cache: