The incident happened in Rose Hill near Gloucester Gardens at around 4.30pm yesterday (August 9).
Officers and London Ambulance Service crews attended and found a girl injured.
She was taken to hospital where her injuries were assessed as non life threatening.
No arrests have been made as police enquiries continue.
A spokesperson for Metropolitan Police said: “Police were called to a report of a collision involving a car and a child on Rose Hill, Sutton at around 4.30pm on Saturday, 9 August.
“A girl, aged 13, was taken to hospital with injuries which are being treated as non-life-threatening or life changing at this time.
“No arrests have been made.
“Anyone with any information or footage is asked to contact 101 or post on ‘X’ @MetCC quoting CAD 4730/09Aug.”
