diff --git a/requirements.txt b/requirements.txt
index 439a8d6999b7..40d8dae202cb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,11 @@
+# Install flake8 first, as both flake8 and autopep8 require pycodestyle,
+# but flake8 has a tighter pinning.
+flake8
 autopep8
 yapf
 pylint
 pep8
 prospector
-flake8
 pydocstyle
 nose
 pytest