The garage was stolen from a house in the grounds of the Orchardbank Industrial Estate in Forfar, Scotland.
Police said the garage would have taken several days to dismantle and would have required a large vehicle or trailer to remove it from the site.
The residents had been away for two weeks and discovered the theft when they returned yesterday.
As well as the garage, a pair of 6 feet tall ornate metal gates and four concrete paving stones were also taken.
A spokesman for Police Scotland's Tayside division said: "It's likely that whoever is responsible for this theft carried out the dismantling of the garage over a period of days".
"Officers are keen to speak to anyone who may have seen or heard anything suspicious in the area," he said.