Three fire engines were called out to vehicles on fire at a car show room on Station Road in Chapeltown just after 10pm on Tuesday night.
Fire crews from Elm Lane, Tankersley and Rivelin stations arrived to find three cars and two vans on fire on the forecourt. The fire also spread slightly to the ouside of the show room.
Firefighters used hose reels to tackle the blaze.
Fire crews left the scene at 12:30am.
It is believed that the fire was started deliberately.