The call came in just after 4 p.m. The fire appeared to be at a home located along a stretch of Dupont between Shaw Street and Ossington Avenue.
Toronto Fire Services later tweeted that the "main body" of the fire was knocked down at 4:27 p.m.
Police are advising the public to stay away from the area.
A handful of photos posted on Twitter showed flames that were visible at the top of a home.
Other photos from the area captured black plumes of smoke emanating from the scene of the fire.
The TTC says that buses on its 63 Ossington route are diverting in both directions as a result of the fire.
The Sunday afternoon fire occurred hours after another fire on Dupont Street claimed a man's life.