Maisie Fox, aged 15 and from Crosspool, was dropped off by her mum near to St Mary’s Gate and Eyre Street at 4pm to meet friends.
She spoke to her sister on the phone at 6.45pm but has not been seen or heard from since.
Maisie is around 6ft tall, of a medium build and has long, brown hair.
She was last seen wearing black leggings, white trainers and a black coat with a black fur hood. She was carrying a black Michael Kors handbag.
Maisie is described as looking older than 15.
It is believed that she has friends in Barnsley and may have made her way there last night.
Anyone with information on her whereabouts should call South Yorkshire Police on 101 and quote incident number 881 of October 6.