diff --git a/.travis.yml b/.travis.yml
index 1d065b178..a5214057d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,7 +39,6 @@ install:
   - pip install -U pip setuptools
   - pip install docutils==$DOCUTILS
   - pip install .[test,websupport]
-  - pip install flake8
   - if [[ $TRAVIS_PYTHON_VERSION == '3.6' ]]; then python3.6 -m pip install mypy typed-ast; fi
 script:
   - flake8
diff --git a/setup.py b/setup.py
index 10a513166..5c0b70959 100644
--- a/setup.py
+++ b/setup.py
@@ -72,6 +72,7 @@ extras_require = {
         'pytest',
         'pytest-cov',
         'html5lib',
+        'flake8',
     ],
     'test:python_version<"3"': [
         'enum34',
diff --git a/tox.ini b/tox.ini
index 00b3c99e2..2ea05641b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -38,7 +38,6 @@ deps=
     {[testenv]deps}
 
 [testenv:flake8]
-deps=flake8
 commands=flake8
 
 [testenv:pylint]