The fire broke out around 10:30 p.m. in the Godfrey Arms development in the 1700 block of West Godfrey Avenue.
The 71-year-old victim was found dead inside her apartment.
Firefighters were able to rescue three people from the complex.
Philadelphia Fire Commissioner Adam Thiel commended the firefighters on their work at the scene.
"Our thoughts and prayers go out to the family of the person here who was apparently lost, but again an incredible job by our firefighters rescuing those other individuals," he said.
The Red Cross is helping dozens of people displaced by the fire.
The cause of the fire is under investigation.