John Hay, 2nd Marquess of Tweeddale (1645 - 20 April 1713) was a Scottish nobleman.

Hay was the eldest son of John Hay, 1st Marquess of Tweeddale.

In 1666, at Highgate in London, he married Lady Mary Maitland, daughter of John Maitland, 1st Duke of Lauderdale (1616-82). However, Lauderdale set himself against Hay, who was forced to leave for the continent and did not regain his position until Lauderdale's death in 1682.

Col Militia Regt of Foot Haddingshire 1668-Jan 1674/5 and Linlithgowshire and Peebleshire 1682

He was created a privy councillor in 1689 and became Lord Treasurer in 1695. He succeeded his father to the Marquessate in 1697.

He was appointed Lord High Commissioner to the Scots Parliament in 1704, and was Lord Chancellor of Scotland from 1704-5. He led the squadrone volante, but ultimately supported the Union. He was appointed a Scottish representative peer in 1707.

His eldest son, Charles (c. 1670-1715), became 3rd marquess. A younger son, Lord John Hay (d. 1706), commanded the famous regiment of dragoons, afterwards called the Scots Greys, at the battle of Ramillies and elsewhere.

Hay was prominent in the stormy times prior to the Act of Union (1707) and was leader of the New Party or Squadrone Volante, which at first opposed the Union and then supported it. He was briefly Lord High Commissioner, or leader, of the Scottish Parliament (1703-4) and became one of the first of the Scottish Representative Peers.

Hay died at Yester and is buried there.

• Wikipedia Entry
• An Historical Account of the Senators of the College of Justice: From Its Institution in MDXXXII; by George Brunton, David Haig; 1832; Page 477