diff --git a/awx/main/tasks.py b/awx/main/tasks.py
index 5a287a1444..09014d9da6 100644
--- a/awx/main/tasks.py
+++ b/awx/main/tasks.py
@@ -2554,7 +2554,7 @@ class RunInventoryUpdate(BaseTask):
             args.append('--exclude-empty-groups')
         if getattr(settings, '%s_INSTANCE_ID_VAR' % src.upper(), False):
             args.extend(['--instance-id-var',
-                        getattr(settings, '%s_INSTANCE_ID_VAR' % src.upper()),])
+                        "'{}'".format(getattr(settings, '%s_INSTANCE_ID_VAR' % src.upper())),])
         # Add arguments for the source inventory script
         args.append('--source')
         args.append(self.pseudo_build_inventory(inventory_update, private_data_dir))