Four fire engines and around 25 firefighters tackled a fire at a residential building on Tinworth Street in Lambeth.
An extractor fan in a communal kitchen was destroyed. Around 100 people left the building before the Brigade arrived. There were no reports of any injuries.
The fire is believed to have been accidental and was caused by a build up of grease in an extractor fan.
The Brigade was called at 1750 and Control Officers mobilised crews from Lambeth, Soho and Dowgate fire stations to the scene. The fire was extinguished by 1820.