diff --git a/requirements/dev.txt b/requirements/dev.txt
index 4989ba5..fe832d4 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -24,3 +24,5 @@ isort==4.2.15
 lazy-object-proxy==1.3.1
 pylint==1.7.4
 wrapt==1.10.11
+pydocstyle==2.1.1
+snowballstemmer==1.2.1
diff --git a/src/__init__.py b/src/__init__.py
index e69de29..cbe7d74 100644
--- a/src/__init__.py
+++ b/src/__init__.py
@@ -0,0 +1 @@
+"""Source code for pgtq."""
diff --git a/src/pgtq.py b/src/pgtq.py
index a5a1fb9..4f6b18f 100644
--- a/src/pgtq.py
+++ b/src/pgtq.py
@@ -1,4 +1,4 @@
-"""A task queue"""
+"""A task queue."""
 import select
 import psycopg2.extras
 import handler
diff --git a/src/worker.py b/src/worker.py
index 9dde3a6..b75f2d8 100644
--- a/src/worker.py
+++ b/src/worker.py
@@ -31,11 +31,11 @@ def poll_loop(queue):
 def main_loop(queue):
     """Continually fetch and handle tasks from the given queue.
 
-       Starts by polling for tasks in a tight loop. If no tasks arrive
-       for MAX_POLLING_IDLE_TIME, go to sleep until notified by the
-       database that another task is ready.
+    Starts by polling for tasks in a tight loop. If no tasks arrive
+    for MAX_POLLING_IDLE_TIME, go to sleep until notified by the
+    database that another task is ready.
 
-       This function does not return.
+    This function does not return.
     """
     while True:
         try:
diff --git a/tox.ini b/tox.ini
index 7b2fd56..7151ec7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py35,flake8,pylint
+envlist = py35,flake8,pylint,pydocstyle
 skipsdist = True
 
 [coverage:run]
@@ -17,6 +17,12 @@ deps = -rrequirements/common.txt
        -rrequirements/dev.txt
 commands=flake8 src tests
 
+[testenv:pydocstyle]
+basepython=python
+deps = -rrequirements/common.txt
+       -rrequirements/dev.txt
+commands=pydocstyle src tests
+
 [testenv:pylint]
 basepython=python
 deps = -rrequirements/common.txt