Four fire engines and around 25 firefighters tackled a fire on Darwin Road in South Ealing.
Half of a room on the first floor of a two-storey terraced house was damaged by fire. One woman was rescued from the property by firefighters via an internal staircase. She was taken to hospital by London Ambulance Service crews.
The Brigade was called at 0409 and Control Officers mobilised crews from Ealing, Acton, Chiswick and Heston fire stations to the scene. The fire was fully extinguished by 0549.
The cause of the fire is under investigation by the Brigade and Metropolitan Police.