diff --git a/phing/build.yml b/phing/build.yml
index 4941f91a9c..483406617b 100644
--- a/phing/build.yml
+++ b/phing/build.yml
@@ -18,6 +18,7 @@ composer:
   bin: ${repo.root}/vendor/bin
 
 deploy:
+  build-dependencies: true
   dir: ${repo.root}/deploy
   exclude_file: ${blt.root}/phing/files/deploy-exclude.txt
   gitignore_file: ${blt.root}/phing/files/.gitignore
diff --git a/phing/tasks/deploy.xml b/phing/tasks/deploy.xml
index abbd2d176f..ba080aeb72 100644
--- a/phing/tasks/deploy.xml
+++ b/phing/tasks/deploy.xml
@@ -87,14 +87,25 @@
   </target>
 
   <target name="deploy:composer:install" description="Downloads core and contrib to deploy folder.">
-    <delete dir="${deploy.dir}/vendor"/>
-    <copy todir="${deploy.dir}" overwrite="true">
-      <fileset dir="${repo.root}">
-        <include name="composer.json"/>
-        <include name="composer.lock"/>
-      </fileset>
-    </copy>
-    <exec dir="${deploy.dir}" command="export COMPOSER_EXIT_ON_PATCH_FAILURE=1; composer install --no-dev --prefer-dist --no-interaction" passthru="true" logoutput="true" checkreturn="true"/>
+    <if>
+      <equals arg1="build-dependencies" arg2="true"/>
+      <then>
+        <echo>Rebuilding composer dependencies without require-dev.</echo>
+        <delete dir="${deploy.dir}/vendor"/>
+        <copy todir="${deploy.dir}" overwrite="true">
+          <fileset dir="${repo.root}">
+            <include name="composer.json"/>
+            <include name="composer.lock"/>
+          </fileset>
+        </copy>
+        <exec dir="${deploy.dir}" command="export COMPOSER_EXIT_ON_PATCH_FAILURE=1; composer install --no-dev --prefer-dist --no-interaction" passthru="true" logoutput="true" checkreturn="true"/>
+      </then>
+      <else>
+        <echo>Dependencies will not be built because deploy.build-dependencies is not enabled.</echo>
+        <echo>You should define a custom deploy.exclude_file to ensure that dependecies are copied from the root repository.</echo>
+      </else>
+    </if>
+
   </target>
 
   <target name="deploy:copy" description="Copy required files from /docroot/sites to /deploy/docroot/sites.">
diff --git a/readme/committing-dependencies.md b/readme/committing-dependencies.md
new file mode 100644
index 0000000000..c3be36ebda
--- /dev/null
+++ b/readme/committing-dependencies.md
@@ -0,0 +1,45 @@
+# Committing Dependencies
+
+Composer's official stance is that you should not commit dependencies.
+
+However, there are sometimes extenuating circumstances that require you to commit your dependencies. In this case, you can commit your dependencies by following these steps:
+
+* Modify your project's `.gitignore` by removing the following lines:
+
+        docroot/core
+        docroot/modules/contrib
+        docroot/themes/contrib
+        docroot/profiles/contrib
+        docroot/libraries
+        drush/contrib
+        vendor
+
+* Create a custom deploy.exclude_file and reference its location in your project.yml
+
+        mkdir blt/deploy && cp vendor/acquia/blt/scripts/files/deploy-exclude.txt blt/deploy/deploy-exclude.txt
+        
+        deploy:
+          exclude_file: ${repo.root}/blt/deploy/deploy_exclude.txt
+
+* Modify your custom deploy_exclude.txt file by removing the following lines:
+
+        /docroot/core
+        /docroot/libraries/contrib
+        /docroot/modules/contrib
+        /docroot/sites/*/files
+        /docroot/sites/*/private
+        /docroot/themes/contrib
+        /drush/contrib
+        /vendor
+
+* Set `deploy.build-dependencies` to `false` in your `project.yml` file:
+
+        deploy:
+          build-dependencies: false
+
+* Commit your changes and dependencies:
+
+        git add -A
+        git commit -m 'Committing dependencies.'
+
+Your dependencies will now be committed to your repository and copied to your deployment artifact.