Sir John Leonard Knox (6 April 1925 – 28 May 2015) was a British High Court judge, sitting in the Chancery division.

Leonard Needham Knox of an Ulster-Scots origin and Berthe Hélène Brel of Lille.

[1] Prior to his elevation to the bench, Sir John practised as a barrister from what is now termed Radcliffe Chambers.

He married secondly in 1993 Benedicta Eugénie, daughter of oboist Léon Goossens and widow of Robin Philip Cooksey.

[1] Notable judicial decisions that Knox J was involved in included: