Eight fire engines and around 60 firefighters tackled a fire on Strasburg Road in Battersea.
Part of a split-level maisonette flat on the ninth and tenth floors of a 13-storey residential block was damaged by fire. Three people left the flat before firefighters arrived and there were no reports of any injuries.
Station Commander Stephen Irvine, who attended the scene, said: "One of the occupants of the flat discovered a well-developed fire in a bedroom.
"They did the right thing by quickly shutting the bedroom door which contained the fire and prevented any fire spread to the rest of the property and importantly ensuring no one was hurt in the incident.
"Firefighters recommend that you have a look at our online Home Fire Safety Checker to make sure there are no hidden hazards in your home.
"The online tool will ask you a series of questions that will help us work out the level of risk in your home, or the home of someone you care for. It only takes a few minutes to get tailored advice to keep yourself and loved ones safe from fire."
The Brigade's 999 Control Officers received 20 calls about the fire.
The Brigade was called at 1923 and the fire was brought under control by 2059. Crews from Battersea, Clapham, Lambeth, Fulham, Brixton and surrounding fire stations attended the scene. A 32-metre turntable ladder from Clapham Fire Station also attended alongside three fire and rescue units and two Command Units.
The cause of the fire is under investigation.