diff --git a/phing/build.yml b/phing/build.yml
index 2e1f9a842..4e72f9722 100644
--- a/phing/build.yml
+++ b/phing/build.yml
@@ -64,6 +64,9 @@ deploy:
   exclude_file: ${blt.root}/phing/files/deploy-exclude.txt
   exclude_additions_file: ${repo.root}/blt/deploy-exclude-additions.txt
   gitignore_file: ${blt.root}/phing/files/.gitignore
+  git:
+    # If true, deploys will fail if there are uncommitted changes.
+    failOnDirty: true
 
 # File and Directory locations.
 docroot.relative: ${repo.root.relative}/docroot
diff --git a/phing/tasks/deploy.xml b/phing/tasks/deploy.xml
index 175ac8965..f618676c2 100644
--- a/phing/tasks/deploy.xml
+++ b/phing/tasks/deploy.xml
@@ -1,7 +1,28 @@
 <project name="deploy" default="deploy">
 
   <target name="deploy" description="Builds separate artifact and pushes to git.remotes defined project.yml.">
-
+    
+    <!-- Check working tree state. -->
+    <exec dir="${repo.root}" command="status=$(git status --porcelain); echo ${#status};"
+          outputProperty="git.status.length" checkreturn="true"/>
+    <if>
+      <!-- Length will be a non-zero value if there are uncommitted changes. -->
+      <not><equals arg1="${git.status.length}" arg2="0"/></not>
+      <then>
+        <if>
+          <!-- Warn that there are uncommitted changes in this deploy. -->
+          <isfalse value="${deploy.git.failOnDirty}"/>
+          <then>
+            <echo level="warning">Deploy is being run with uncommitted changes.</echo>
+          </then>
+          <!-- Fail the deploy, the working tree must be clean. -->
+          <else>
+            <fail>There are uncommitted changes, commit or stash these changes before deploying.</fail>
+          </else>
+        </if>
+      </then>
+    </if>
+    
     <!-- Build some defaults -->
     <exec command="git rev-parse --abbrev-ref HEAD" dir="${repo.root}" outputProperty="branch.current"/>
     <exec command="git log --oneline -1" dir="${repo.root}" outputProperty="deploy.commitMsg.last"/>
diff --git a/scripts/travis/deploy_branch b/scripts/travis/deploy_branch
index 82e79cfc6..892bf37e1 100755
--- a/scripts/travis/deploy_branch
+++ b/scripts/travis/deploy_branch
@@ -2,6 +2,6 @@
 
 set -ev
 
-blt deploy -Ddeploy.commitMsg="Automated commit by Travis CI for Build ${TRAVIS_BUILD_ID}" -Ddeploy.branch="${TRAVIS_BRANCH}-build"
+blt deploy -Ddeploy.commitMsg="Automated commit by Travis CI for Build ${TRAVIS_BUILD_ID}" -Ddeploy.branch="${TRAVIS_BRANCH}-build" -Ddeploy.git.failOnDirty=false
 
 set +v
diff --git a/scripts/travis/deploy_tag b/scripts/travis/deploy_tag
index 0203b27b5..0f3bf3e3f 100755
--- a/scripts/travis/deploy_tag
+++ b/scripts/travis/deploy_tag
@@ -2,6 +2,6 @@
 
 set -ev
 
-blt deploy -Ddeploy.commitMsg="Automated commit by Travis CI for Build ${TRAVIS_TAG}" -Ddeploy.tag="${TRAVIS_TAG}-build"
+blt deploy -Ddeploy.commitMsg="Automated commit by Travis CI for Build ${TRAVIS_TAG}" -Ddeploy.tag="${TRAVIS_TAG}-build" -Ddeploy.git.failOnDirty=false
 
 set +v