William Hay, 1st Earl of Erroll (1423 – October 1462) was a Scottish peer.

[1] His paternal grandfather Thomas de la Hay was the third Lord High Constable of Scotland.

On 17 March 1452, King James II of Scotland made him the first Earl of Erroll.

Some historians list his death as August 1460, but Sir James Balfour Paul notes in The Scots Peerage that Kinnoull was alive in the Slains land inventory of November 1461.

Balfour writes that the earl likely died in October 1462,[3] and was interred in the Abbey Church of Cupar.