diff --git a/tox.ini b/tox.ini
index 70e820e..62c57d0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,8 +6,12 @@ deps = pytest
 commands = pytest
 
 [testenv:pycodestyle]
-deps = pycodestyle
-commands = pycodestyle ./stix2
+deps =
+  flake8
+  pycodestyle
+commands =
+  pycodestyle ./stix2
+  flake8 --max-line-length=160
 
 [pycodestyle]
 ignore=