Multiple residents were forced out onto their balconies to escape the smoke and had to be rescued from them, Toronto Fire Services said.
Some residents evacuated the building. Others were trapped inside the garbage room on the fourth floor, the department said.
Fire crews were called at 9:24 p.m. to the apartment building. The fire was mostly extinguished by 9:45 p.m., but additional resources were called in to ensure the fire was out and to clear the smoke.
No residents were transported to hospital, according to Toronto Emergency Medical Services, though some complained of smoke inhalation. Fire Department officials did not have an estimate of the damages Sunday morning.