Six fire engines and around 40 firefighters tackled a flat fire on Lansdowne Lane in Charlton.
Half of a communal hallway on the second floor of a residential block was damaged by fire. One woman was treated on scene.
The Brigade was called at 1909 and the fire was under control by 1953. Fire crews from East Greenwich, Plumstead and Greenwich fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.