The incident happened at the junction of Parchmore Road and Green Lane at 9pm yesterday (July 1).
Officers, London Ambulance Service crews, and London Fire Brigade were called to the scene.
The driver of one of the cars, a woman, was taken to hospital for further treatment.
Her injuries were later assessed as not life-threatening or life changing.
The occupants of one of the other cars reportedly left the scene before police arrived.
A spokesperson for Metropolitan Police said: “Police were called at 9pm on Saturday, 1 July to reports of a collision involving three cars at the junction of Parchmore Road and Green Lane, Thornton Heath.
“Officers attended along with the London Ambulance Service and the London Fire Brigade.
“The driver of one of the cars, a woman in her 20s, was taken to hospital.
“Her injuries were assessed as not life-threatening or life-changing.
“The occupants of one of the other cars involved reportedly left the scene before officers arrived.
“Enquiries are ongoing and any witnesses are asked to call 101 quoting CAD 7245/01Jul.”
