More than 50 firefighters and six fire engines, plus specialist appliances, raced to the scene on Scotland Street at about 5am this morning (Tuesday).
They found the single-storey garage alight with a number of cars on fire, and gas cylinders stored in the area.
The Scottish Fire and Rescue Service said there were no casualties and the blaze was extinguished shortly after 10am.
No one is thought to have been injured.
Scotland Street was closed to traffic between Carnoustie Street and Shields Roa, while the car park at Shields Road subway was also closed.
Both have since reopened.