diff --git a/pungi/phases/image_build.py b/pungi/phases/image_build.py
index 3fce8871..cca9eeb4 100644
--- a/pungi/phases/image_build.py
+++ b/pungi/phases/image_build.py
@@ -33,7 +33,7 @@ EXTENSIONS = {
     'vagrant-virtualbox': ['vagrant-virtualbox.box'],
     'vagrant-vmware-fusion': ['vagrant-vmware-fusion.box'],
     'vdi': ['vdi'],
-    'vmdk': ['vdmk'],
+    'vmdk': ['vmdk'],
     'vpc': ['vhd'],
     'vsphere-ova': ['vsphere.ova'],
 }