Four fire engines and around 25 firefighters were called to Fountain Road at around 1.30pm today (Friday, January 5).
Part of a first-floor flat is alight. Two women escaped the blaze before fire crews arrived.
All those rescued and who escaped the fire are currently being treated at the scene by London Ambulance Service.
The cause of the fire is currently unknown.
A spokesperson for London Fire Brigade said: “Four fire engines and around 25 firefighters are tackling a fire on Fountain Road in Tooting.
“Part of a first-floor flat is alight.
“Two men and two children have been rescued from the flat by firefighters via a nine-metre ladder.
“Two women left the flat before firefighters arrived.
“They are all being treated by London Ambulance Service crews.
“Fountain Road is currently closed and people are asked to avoid the area.
“The Brigade was called at 1.26pm. Firefighters from Tooting, Wimbledon and Wandsworth fire stations are at the scene.
“The cause of the fire is unknown at this time.”