Over 70 firefighters were called to Connington Crescent, Chingford, just before 2.15am on Friday. London Fire Brigade said 12 people left the three-storey block before firefighters arrived.
When the ten fire crews arrived, two floors and the roof of the building were alight, London Fire Brigade (LFB) said, paramedics treated a female resident, but she was pronounced dead at the scene.
Station manager Keith Wilson said: “Firefighters have been working hard to contain the spread of the fire which has destroyed the roof.
“Crews expect to be here into the day, tackling hot spots.”
MP for Chingford and Woodford Green Iain Duncan Smith has described the incident a “terrible tragedy”.
The former Tory party leader added: “My heart goes out to victims.”The former Tory party leader added: “My heart goes out to victims.”