Alina Qureshi was last seen by her family at about 10:30pm on Thursday in Halifax (June 27).
Enquiries have shown potential links to the West Midlands, particularly Birmingham and Walsall, and also to London.
She is described as 5ft tall, of slim/medium build, with long straight black hair and brown eyes. She was last seen wearing a grey Nike jumper, black shirt, black Adidas shoes and had a pink leather shoulder bag.
Anyone who has seen her or who has any information that could assist in tracing her is asked to contact West Yorkshire Police via 101 quoting log 2157 of June 27 or reference 13190326073.