William Hay, 10th Earl of Erroll

The Right Honourable The Earl of Erroll PC
Arms of the Earl of Erroll
14th Lord High Constable of Scotland
In office 1631 – 7 December 1636
Preceded by	Francis Hay
Succeeded by	Gilbert Hay
Personal details
Born	before 1597
Died	7 December 1636 Errol, Scotland

William Hay, 10th Earl of Erroll PC (before 1597 – 7 December 1636) was a Scottish nobleman.

He was the eldest son of Francis Hay, 9th Earl of Erroll by his third wife, Lady Elizabeth, daughter of William Douglas, 6th Earl of Morton.

He succeeded to the earldom after his father's death in 1631. He became a member of the Privy Council on 28 May 1633. He also succeeded to the title of Lord High Constable of Scotland, and took part in the Scottish coronation of King Charles I of Holyrood Abbey on 18 June 1633.

The earl lived such an extravagant lifestyle that he was forced to sell off the family's namesake lands in Errol, which had been granted to his forebearers by King William the Lion in the 12th century.

In September 1618, he married Anne Lyon, only daughter of Patrick Lyon, 1st Earl of Kinghorne. They had issue: