diff --git a/.gitlint b/.gitlint
new file mode 100644
index 0000000000..4287c8d1aa
--- /dev/null
+++ b/.gitlint
@@ -0,0 +1,11 @@
+[general]
+ignore=title-trailing-punctuation, body-min-length, body-is-missing
+
+[title-match-regex]
+regex=^.+\.$
+
+[title-max-length]
+line-length=76
+
+[body-max-line-length]
+line-length=76
diff --git a/.travis.yml b/.travis.yml
index 171c1659ae..38f11d6cbb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,6 +20,7 @@ env:
     - COVERALLS_SERVICE_NAME=travis-pro
     - COVERALLS_REPO_TOKEN=hnXUEBKsORKHc8xIENGs9JjktlTb2HKlG
     - BOTO_CONFIG=/tmp/nowhere
+    - UPSTREAM_MASTER=$(git ls-remote git://github.com/zulip/zulip.git refs/heads/master | cut -f 1)
 language: python
 matrix:
   include:
diff --git a/requirements/dev.txt b/requirements/dev.txt
index b6c9b65313..06137ec05a 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -21,6 +21,13 @@ pyflakes==1.5.0
 # Needed to run tests in parallel
 tblib==1.3.0
 
+# Needed to lint Git commit messages
+gitlint==0.8.1
+
+# Needed for gitlint
+arrow==0.10.0
+sh==1.11
+
 # Needed to sync translations from transifex
 transifex-client==0.12.4
 
diff --git a/tools/commit-msg b/tools/commit-msg
new file mode 100755
index 0000000000..5adf9accec
--- /dev/null
+++ b/tools/commit-msg
@@ -0,0 +1,19 @@
+#!/bin/bash
+
+# This hook runs gitlint on your commit message.
+
+# If your machine contains a provisioned Zulip development environment, the
+# linter will be invoked through `vagrant ssh`.
+
+lint_cmd="cd ~/zulip && cat \"$1\" | python -m gitlint.cli"
+if [ -z "$VIRTUAL_ENV" ] && `which vagrant > /dev/null` && [ -e .vagrant ]; then
+    vagrant ssh -c "$lint_cmd"
+else
+    $lint_cmd
+fi
+
+if [ $? -ne 0 ]; then
+    echo "WARNING: Your commit message does not match Zulip's style guide."
+fi
+
+exit 0
diff --git a/tools/lint-all b/tools/lint-all
index 53a0f2472d..a431df8e2b 100755
--- a/tools/lint-all
+++ b/tools/lint-all
@@ -617,6 +617,9 @@ def run():
     parser.add_option('--pep8',
                       action='store_true',
                       help='Run the pep8 checker')
+    parser.add_option('--no-gitlint',
+                      action='store_true',
+                      help='Disable gitlint')
     parser.add_option('--modified', '-m',
                       action='store_true',
                       help='Only check modified files')
@@ -687,6 +690,9 @@ def run():
         external_linter('templates', ['tools/check-templates'], ['handlebars', 'html'])
         external_linter('urls', ['tools/check-urls'])
 
+        if not options.no_gitlint:
+            external_linter('commit_messages', ['tools/lint-commits'])
+
         @lint
         def custom_py():
             # type: () -> int
diff --git a/tools/lint-commits b/tools/lint-commits
new file mode 100755
index 0000000000..1132966fa2
--- /dev/null
+++ b/tools/lint-commits
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+# Lints all commit messages that are newer than upstream/master.
+# The rules can be found in /.gitlint
+
+# If this script is running on TravisCI, $UPSTREAM_MASTER would be set to the
+# latest HEAD in travis.yml
+if [ ! $TRAVIS ]; then
+    UPSTREAM_MASTER=upstream/master
+fi
+
+gitlint --commits $UPSTREAM_MASTER...HEAD
diff --git a/tools/pre-commit b/tools/pre-commit
index 14ea067e68..0120a4d1a4 100755
--- a/tools/pre-commit
+++ b/tools/pre-commit
@@ -16,10 +16,10 @@ if [ -z "$changed_files" ]; then
 fi
 
 if [ -z "$VIRTUAL_ENV" ] && `which vagrant > /dev/null` && [ -e .vagrant ]; then
-    vcmd="/srv/zulip/tools/lint-all --pep8 --force $changed_files || true"
+    vcmd="/srv/zulip/tools/lint-all --pep8 --no-gitlint --force $changed_files || true"
     echo "Running lint-all using vagrant..."
     vagrant ssh -c "$vcmd"
 else
-    ./tools/lint-all --pep8 --force $changed_files || true
+    ./tools/lint-all --pep8 --no-gitlint --force $changed_files || true
 fi
 exit 0
diff --git a/tools/setup-git-repo b/tools/setup-git-repo
index 3c21c8677d..6035cee220 100755
--- a/tools/setup-git-repo
+++ b/tools/setup-git-repo
@@ -6,6 +6,7 @@ if ! [ -d ".git/hooks/" ]; then
     exit 1
 fi
 
-for hook in pre-commit; do
+for hook in pre-commit commit-msg
+do
     ln -snf ../../tools/"$hook" .git/hooks/
 done
diff --git a/version.py b/version.py
index 4c3587a78c..b788bc5b3b 100644
--- a/version.py
+++ b/version.py
@@ -1,2 +1,2 @@
 ZULIP_VERSION = "1.5.1+git"
-PROVISION_VERSION = '4.17'
+PROVISION_VERSION = '4.18'