Thiess Pty Ltd is an international mining services company based in Brisbane, Australia. Established in the 1930s as Horn & Thiess, the company later became Thiess Bros and Thiess Contractors before being bought by Leighton Holdings in 1983 to become part of the CIMIC Group. Thiess' headquarters are located in the Thiess Centre in South Bank in the Brisbane CBD near the TAFE Brisbane City campus.