Fifteen fire engines and around 100 firefighters tackled a grass fire near Turle Road in Norbury.
Approximately seven hectares of wasteland, shrubs and school playing fields were alight. Around 35 houses have been affected by the fire and 19 residents were evacuated as a precaution. There are currently no reports of any injuries. Crews are expected to remain on scene this afternoon.
The Brigade's 999 Control Officers took more than 100 calls to the blaze.
Assistant Commissioner Jonathan Smith, who was at the scene, said: "Firefighters faced a very intense and serious fire. There is no doubt that the dynamic actions taken by crews immediately on arrival saved more than 40 homes from the blaze.
"Hot and windy conditions made tackling the fire challenging and firefighters worked incredibly hard to save a whole street's worth of houses."
The fire produced heavy smoke in the area and the direction of the wind was blowing smoke towards local terraced houses. We encouraged people to avoid the area and asked local residents to keep windows and doors closed.
The Brigade was called at 1227 and the fire was under control by 1608. Fire crews from West Norwood, Mitcham, Wallington, Norbury, Woodside and surrounding fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.