diff -u b/platform/backup.provision.inc b/platform/backup.provision.inc
--- b/platform/backup.provision.inc
+++ b/platform/backup.provision.inc
@@ -6,6 +6,13 @@
  * Back up an existing site
  */
 
+const PROVISION_BACKUP_EXCLUDED_DIRECTORIES = array(
+  './files/css',
+  './files/js',
+  './private/temp',
+  './.git',
+);
+
 /**
  * Make sure the site is installed and enabled, and that we have a valid target to back up to.
  */
@@ -93,7 +100,7 @@
   }
 
   $command_base = "tar cpf";
-  $command_arguments = " %s --exclude='./private/temp' .";
+  $command_arguments = " %s" . drush_provision_drupal_provision_backup_get_exclusions() . " .";
   if (substr($backup_file, -2) == 'gz') {
     $command = $command_base . 'z' . $command_arguments;
   }
@@ -123,6 +130,14 @@
   }
 }
 
+function drush_provision_drupal_provision_backup_get_exclusions() {
+  $exclusions = "";
+  foreach (PROVISION_BACKUP_EXCLUDED_DIRECTORIES as $directory) {
+    $exclusions .= " --exclude='$directory'";
+  }
+  return $exclusions;
+}
+
 function drush_provision_drupal_post_provision_backup() {
   drush_log(dt('Backed up site up to @path.', array('@path' => drush_get_option('backup_file'))), 'success');
   if (d()->client_name) {