Sir Mark Andrew O'Regan KNZM (born 30 November 1953) is a New Zealand lawyer and jurist.

Born on 30 November 1953[1] and educated at St Patrick's College, Silverstream, O'Regan graduated from Victoria University of Wellington.

[2] He was admitted as a barrister and solicitor of the High Court in 1977 and became a partner with the law firm Chapman Tripp in 1984.

[4] In the 2013 New Year Honours, O'Regan was appointed a Knight Companion of the New Zealand Order of Merit for services to the judiciary.

[5][6] O'Regan is married to the writer Nicola Saker, who in the 2023 King's Birthday and Coronation Honours was appointed a Member of the New Zealand Order of Merit, for services to heritage preservation and the arts.