The girl was at a pedestrian crossing near Horsham Fire Station, on Hurst Road, when she was in collision with a red Volvo Estate car.
It happened between 4pm and 4.25pm on Friday 23 September, and left the girl with minor injuries.
Investigating officers are keen to speak to any witnesses, particularly anyone who may have captured any relevant dash cam footage.
Anyone with information can contact police online or by calling 101 quoting serial 914 of 23/09.