The flames ignited inside a building in the 1300-block of South Christiana near Douglas Boulevard. Flames were blowing out the first-floor windows.
Security guards from other buildings helped alert residents to get out quickly.
The injured woman suffered smoke inhalation. Doctors were treating her at Loyola University Medical Center's burn unit Wednesday.
The fire was out within a half hour.
An investigation is under way to find out what started the fire.