Inmate Andrew John Sharkey, 35, was reported missing from the open prison yesterday afternoon at 5:40pm.
It is believed that he has connections in the Dundee and Perth areas.
He is described as being 5ft 11”, medium build, clean shaven with short brown hair. He was last seen wearing a dark coloured hooded top and khaki coloured trousers.
Should they spot him, members of the public have been warned not to approach Sharkey and instead call Police Scotland on 101 or 999.
The 285 capacity Castle Huntly prison was brought under the control of the government in 1946 after the death of its owner Colonel Adrian Gordon Paterson.
It is the only open prison in the country. Former MSP Tommy Sheridan has previously spent time as an inmate here.