Two fire engines and around 10 firefighters tackled a fire at a detached house on Linksway in Northwood.
Part of a first floor bedroom was damaged by the fire. Two people were rescued by firefighters wearing breathing apparatus and were taken to hospital by London Ambulance Service crews.
The Brigade was called at 2345 and the fire was under control by 0036. Firefighters from Harrow and Hillingdon fire stations attended the scene.
The cause of the fire is under investigation.