Sir John Clarke MacDermott, PC (9 May 1927 – 13 December 2022) was a Northern Ireland barrister and judge.
He was educated at Campbell College, Belfast, Trinity Hall, Cambridge (BA), and Queen's University Belfast.
MacDermott was called to English Bar by the Inner Temple and the Bar of Northern Ireland in 1949 and became a Northern Irish Queen's Counsel in 1964.
He was appointed a Justice of the High Court of Northern Ireland in 1973.
In 1987, he was made a Lord Justice of Appeal, and was knighted and sworn of the Privy Council.