diff --git a/requirements.txt b/requirements.txt
index 2f54179e..c21ca621 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,8 +1,8 @@
-pbr>=0.6,<1.0
 argparse
 iso8601>=0.1.8
+pbr>=0.6,<1.0
 PrettyTable>=0.7,<0.8
 python-keystoneclient>=0.6.0
 PyYAML>=3.1.0
-six>=1.4.1
 requests>=1.1
+six>=1.4.1
diff --git a/test-requirements.txt b/test-requirements.txt
index 8202de34..d85a7b9e 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,11 +1,11 @@
-# Hacking already pins down pep8, pyflakes and flake8
-hacking>=0.8.0,<0.9
 coverage>=3.6
 discover
 fixtures>=0.3.14
+# Hacking already pins down pep8, pyflakes and flake8
+hacking>=0.8.0,<0.9
 mock>=1.0
 mox3>=0.7.0
 sphinx>=1.1.2,<1.2
-testscenarios>=0.4
 testrepository>=0.0.18
+testscenarios>=0.4
 testtools>=0.9.34
diff --git a/tools/requirements_style_check.sh b/tools/requirements_style_check.sh
new file mode 100755
index 00000000..ccbff3bd
--- /dev/null
+++ b/tools/requirements_style_check.sh
@@ -0,0 +1,32 @@
+#!/bin/bash
+#
+# Enforce the requirement that dependencies are listed in the input
+# files in alphabetical order.
+
+# FIXME(dhellmann): This doesn't deal with URL requirements very
+# well. We should probably sort those on the egg-name, rather than the
+# full line.
+
+function check_file() {
+    typeset f=$1
+
+    # We don't care about comment lines.
+    grep -v '^#' $f > ${f}.unsorted
+    sort -i -f ${f}.unsorted > ${f}.sorted
+    diff -c ${f}.unsorted ${f}.sorted
+    rc=$?
+    rm -f ${f}.sorted ${f}.unsorted
+    return $rc
+}
+
+exit_code=0
+for filename in $@
+do
+    check_file $filename
+    if [ $? -ne 0 ]
+    then
+        echo "Please list requirements in $filename in alphabetical order" 1>&2
+        exit_code=1
+    fi
+done
+exit $exit_code
diff --git a/tox.ini b/tox.ini
index 98100ae8..6e02d81d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,6 +13,7 @@ commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:pep8]
 commands = flake8
+           {toxinidir}/tools/requirements_style_check.sh requirements.txt test-requirements.txt
 
 [testenv:venv]
 commands = {posargs}