The fire was reported around 1:30 a.m. Saturday in the 9800 block of Haldeman Avenue.
Firefighters arrived to find flames in the first-floor apartment.
The woman who was injured suffered burns to more than 70 percent of her body.
Firefighters had to evacuate residents from the 2nd and 3rd floors, but fortunately no one else was injured.
There was no word on what sparked the flames.