diff --git a/doc/source/middlewarearchitecture.rst b/doc/source/middlewarearchitecture.rst
index a3ee08ce..2df21eb5 100644
--- a/doc/source/middlewarearchitecture.rst
+++ b/doc/source/middlewarearchitecture.rst
@@ -203,8 +203,8 @@ they've been stored in the cache may continue to work. Deployments using
 `memcached`_ may use the following keystonemiddleware configuration options
 instead of an in-memory cache.
 
-* ``memcached_servers``: (optional) if defined, the memcached server(s) to use for
-  caching. It will be ignored if Swift MemcacheRing is used instead.
+* ``memcached_servers``: (optional) if defined, the memcached server(s) to use
+  for caching. It will be ignored if Swift MemcacheRing is used instead.
 * ``token_cache_time``: (optional, default 300 seconds) Set to -1 to disable
   caching completely.
 
diff --git a/test-requirements.txt b/test-requirements.txt
index e28d0b6c..1c442cb5 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -7,6 +7,7 @@ flake8-docstrings==0.2.1.post1 # MIT
 
 coverage!=4.4,>=4.0 # Apache-2.0
 cryptography!=2.0,>=1.6 # BSD/Apache-2.0
+doc8 # Apache-2.0
 docutils>=0.11 # OSI-Approved Open Source, Public Domain
 fixtures>=3.0.0 # Apache-2.0/BSD
 mock>=2.0.0 # BSD
diff --git a/tox.ini b/tox.ini
index e9d9b564..9e3ececf 100644
--- a/tox.ini
+++ b/tox.ini
@@ -51,6 +51,7 @@ exclude = .venv,.tox,dist,doc,*egg,build
 
 [testenv:docs]
 commands=
+    doc8 doc/source
     python setup.py build_sphinx
 
 [testenv:releasenotes]
@@ -59,3 +60,8 @@ commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasen
 [hacking]
 import_exceptions =
     keystonemiddleware.i18n
+
+[doc8]
+extensions = .rst, .yaml
+# lines should not be longer than 79 characters.
+max-line-length = 79