Dean Cambage (pictured) absconded from the Grendon Underwood open prison at about 8.30am on April 7.
The 31 year old is not thought to be a risk to himself or the public.
Cambage is white, 5ft 11ins, of medium build with short brown hair.
Call police on 101 if you see him or have information of his whereabouts, or call Crimestoppers anonymously on 0800 555 111.