Peter Francis Walter Kerr, 12th Marquess of Lothian, KCVO (8 September 1922–11 October 2004) was a British peer, politician and landowner. He married Antonella Newland on 30 April 1943 and Lord and Lady Lothian had six children: two sons and four daughters. His elder son, the Conservative politician the Earl of Ancram (known commonly as Michael Ancram), succeeded to the Marquessate on his death, while his third and fourth daughters married the Heirs Apparent to the Duke of Grafton and the Duke of Buccleuch and Queensberry respectively.