Kalisha Daley was last seen leaving school at around 3.15pm on Friday.
South Yorkshire Police have not provided details of which school Kalisha was leaving when she was last seen, but have confirmed she is from the Woodthorpe area.
A spokesman said: Kalisha is 5ft 2ins, slim and with black wavy hair parted with extensions.
"She was wearing ripped blue jeans and a black leather jacket
"She was carrying a black handbag bearing the words 'New Look' and may have been wearing glasses."
Anyone with information is asked to call South Yorkshire Police on 101, quoting incident number 689.