Amarylis Harris-Pearce, also known as Amber, was last sighted at Westbury railway station yesterday (12/04) boarding the 3.03pm train to Portsmouth but was thought to be travelling towards Andover.
She is described as being white, around 5ft 7ins tall, of a slim build, with brown-blonde shoulder-length hair.
She was wearing a white crop top under a black puffa jacket with black leggings, striped slider-style shoes and white socks.
Police are concerned for her welfare.
If you see Amarylis, please contact us on 101 quoting reference 54230038533.