Alexander Moncrieff, Lord Moncrieff FRSE (14 August 1870 – 5 August 1949), was a Scottish lawyer and judge, who was created a Senator of the College of Justice.

Alexander Moncrieff was the third son Alexander Moncrieff, Advocate and Sheriff of Ross and Cromarty, and Hope Margaret, née Pattison.^[1]

Moncrieff studied law at the universities of Glasgow and Edinburgh.^[2]

In 1894 Moncrieff was called to the Scottish bar and in 1912 he became a King's Counsel.^[3] At this time he was living at 11 Lynedoch Place in Edinburgh's West End.^[4]

In January 1926 he was created a Senator of the College of Justice with the title of Lord Moncrieff.^[5] He was the judge for the original trial in Donoghue v. Stevenson.

In 1941 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were Thomas Graham Robertson, Lord Robertson, Sir Edmund Taylor Whittaker, John Alexander Inglis and Sir Ernest Wedderburn.^[6]

He became Lord Justice Clerk in February 1947, succeeding Lord Cooper,^[2][7] but resigned later that year on the grounds of ill-health.^[8] In May 1947, he became a Privy Counsellor.

He died at his home in Edinburgh on 5 August 1949.^[1]

In 1913, Moncrieff married a widow, Helen Spens (née McClelland Adams). They had three children: Helen Margaret Moncrieff (who went on to become well known as a cellist), Hugh, and Philip.^[1]

Moncrieff's daughter, Margaret Moncrieff, married the well-known Scottish pianist Alexander Kelly; and they had two daughters, Catriona Helen Moncrieff Kelly and Alison Mary Moncrieff Kelly. Catriona is Professor of Russian at New College, Oxford; and Alison is a cellist. Alison has two children, Alexander Davan Wetton and Camilla Davan Wetton.^{[citation needed]}