William Hare (born 1792 or 1804) was an Irish serial killer who, along with William Burke committed a notorious series of murders in Edinburgh in the 19th century.

His birthplace is as uncertain as his birth date, being variously given as Newry or Derry. He emigrated to Scotland and worked as a labourer on the Union Canal. He then moved to Edinburgh where he met a man named Logue. When Logue died in 1826, he took Margaret Laird, Logue's widow, as his common-law wife and the two ran a lodging house.

Main article West Port murders
Hare confessed to the murders and gave evidence against Burke in return for his freedom. As a result, Burke was hanged. Released the following February, there are various conflicting and unreliable accounts of Hare's later life, none of which records his eventual death:

Deciding to lie low, Hare travelled to Kilkeel and eventually sought relief in the workhouse. His identity was only revealed to the locals when a Dr Reid, a former medical student from Edinburgh, recognized him.
Hare migrated to Carlisle, England and disappeared from history.
A lynch mob blinded him and threw him into a lime pit.
Hare moved to London and died there destitute in 1859.