The incident happened around 3.50 p.m. on Thursday January 25 on Haddington Road, near to the Aldi supermarket.
Police in East Lothian are appealing for witnesses following a serious road collision in Tranent.
The girl sustained a number of injuries and was taken to the Sick Kids Hospital in Edinburgh, where she remains in a serious condition.
Inquiries into the full circumstances surrounding the collision are ongoing and anyone with information is asked to come forward.
Sergeant Neil Inglis from the Lothians and Scottish Borders Road Policing Unit said: “The driver stopped as soon as the incident occurred and is continuing to assist with our investigation, but we are also keen to hear from other members of the public who witnessed what happened.
“If you were on Haddington Road on Thursday afternoon and believe you have information relevant to this inquiry then please contact police immediately.”
Those with information can contact the Lothians and Scottish Borders Road Policing Unit via 101 and quote incident number 2300 of the 25th January.