Karla Richardson was dropped off in Doncaster town centre at 11am on Saturday May 20 and should have returned home by 4pm the same day, but did not.
She is described as being white, of slim build and between 5ft 2in and 5ft 3in tall.
She has blonde shoulder length hair and was wearing black glasses.
She was last seen wearing a thin layered cream jacket with flower motifs a white top, black leggings and black ankle boots.
Anyone with information as to her whereabouts is asked to call South Yorkshire Police on 101.