The doll, worth around £2,500, belongs to a 10-year-old girl who has an attachment disorder.
It was stolen from the boot of a Citroen DS3 parked at Asda, on Avon Road, Cannock, between 1pm and 2.30pm on Tuesday, May 11.
The theft was only reported to Staffordshire Police on Sunday, May 23.
Officers are currently reviewing CCTV footage and ask anyone with information to contact Staffordshire Police on 101, quoting incident number 083 of 23 May.
Alternatively, contact Crimestoppers anonymously on 0800 555111 or at crimestoppers-uk.org