Between 11pm and 11.30pm on January 14, offenders entered the building by forcing entry through the roof.
Once inside, they broke into cabinets and stole jewellery and watches before leaving the premises. No one else was in the store at the time.
Anyone with any information should contact the Thames Valley Police enquiry centre on 101.
The investigating officer is Det Sgt Richard White from Witney Local CID.
