Sir William Leighton, Bt. was a British shipowner and merchant who served as the Lord Mayor of London in 1806. Leighton's family was from County Durham in the North East of England and he moved to London around 1779 following his fathers death. Leighton worked as a coal merchant shipping coal from the port of Newcastle, and was based a Newcastle's Coal Exchange. Leighton was a prominent shipowner, and owned the Borrowdale, Fishburn and Golden Grove ships, three of the ships of the First Fleet transporting convicts to the British colony of Australia. Leighton also owned several ships which were sent as military transports to the British Province of Quebec with contracts from the British Navy. Leighton also served on various shipping committees. Leighton was listed as one of the governors of Christ's Hospital in 1825.