The title Earl of Erroll is an ancient one in the Peerage of Scotland. It was created in 1453 for Sir William Hay.

The subsidiary titles held by the Earl of Erroll are: Lord Hay (created 1449) and Lord Slains (1452), both in the Peerage of Scotland. The Earls of Erroll also hold the hereditary office of Lord High Constable of Scotland. The office was once associated with great power.

The Earl of Erroll is one of thee peers entitled to appoint a private pursuivant, with the title "Slains".

Earls of Erroll (1453)

• William Hay, 1st Earl of Erroll (d. c. 1462)
• Nicholas Hay, 2nd Earl of Erroll (d. 1470)
• William Hay, 3rd Earl of Erroll (d. 1507)
• William Hay, 4th Earl of Erroll (d. 1513)
• William Hay, 5th Earl of Erroll (d. 1541)
• William Hay, 6th Earl of Erroll (c. 1521-1541)
• George Hay, 7th Earl of Erroll (d. 1573)
• Andrew Hay, 8th Earl of Erroll (d. 1585)
• Francis Hay, 9th Earl of Erroll (d. 1615)
• William Hay, 10th Earl of Erroll (d. 1636)
• Gilbert Hay, 11th Earl of Erroll (d. 1675)
• John Hay, 12th Earl of Erroll (d. 1704)
• Charles Hay, 13th Earl of Erroll (d. 1717)
• Mary Hay, 14th Countess of Erroll (d. 1758)
• James Hay, 15th Earl of Erroll (1726-1778)
• George Hay, 16th Earl of Erroll (1767-1798)
• William Hay, 17th Earl of Erroll (1772-1819)
• William George Hay, 18th Earl of Erroll (1801-1846)
• William Harry Hay, 19th Earl of Erroll (1823-1891)
• Charles Gore Hay, 20th Earl of Erroll (1852-1927)
• Victor Alexander Sereld Hay, 21st Earl of Erroll (1876-1928)
• Josslyn Victor Hay, 22nd Earl of Erroll (1901-1941)
• Diana Denyse Hay, 23rd Countess of Erroll (1926-1978)
• Merlin Sereld Victor Gilbert Moncreiffe, 24th Earl of Erroll (b. 1948)

Heir Apparent: his son Harry Thomas William Hay, Lord Hay (b. 1984 )