West Yorkshire Fire and Rescue Service said crews were called to Seaforth Place, Harehills, shortly before 3.30pm.
Nobody was injured.
It is understood that the fire took place in the kitchen.
A fire investigation officer attended to establish a cause, but this has not been disclosed.
The fire was extinguished using four breathing apparatus, two hose reels and positive pressure ventilation fans were needed to clear the smoke.
A service spokesperson said that smoke detectors were working in the property.
Crews from the Killingbeck and Hunslet stations attended.