Sir Leslie Charles Thiess CBE (8 April 1909 – 25 November 1992) was a construction and mining industry entrepreneur, based in Queensland, Australia.

[1] Under his leadership, the company became a major contractor in Queensland and, when Horn retired in 1939, the firm became Thiess Bros.

[3] After a hostile takeover by CSR in 1979, Thiess lost control of his company but, with assistance from two major backers, he bought back the construction division, continuing to develop coal mines and work on major Queensland government contracts, as well as being granted the licence for a casino in Townsville.

[4][1] Thiess sued Channel 9 for defamation, and won a minimal $55,050 in damages, but the jury found many of the allegations to be true.

It was clear that he had increasingly made use of his closeness to politicians and officials to obtain contracts, sometimes using inducements.