Four fire engines and around 25 firefighters were called to woodland and undergrowth alight in woods on Bostall Hill in Abbey Woods.
Around half a hectare of land was damaged by the fire. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “The warmer weather we have been having makes the ground extremely dry, which unfortunately means grassland, parks, undergrowth and woodlands will burn quickly when exposed to even the smallest of sparks.
“We don’t want people to be complacent and that means not barbecuing in parks and open spaces, ensuring cigarettes are properly disposed of and clearing away rubbish and glass as they can magnify the sun and cause a fire.”
The Brigade was called at 1124 and the fire was under control by 1336. Fire crews from Plumstead, Erith and Bexley fire stations were at the scene.
Brigade top tips on grass fires: