John Conrad Russell, 4th Earl Russell (16 November 1921 – 16 December 1987) was the eldest son of the philosopher and mathematician Bertrand Russell (the 3rd Earl) and his second wife, Dora Black. He was the great-grandson of the 19th century British Whig Prime Minister Lord John Russell.

Married on 28 August 1946 to Susan Doniphan Lindsay, daughter of the poet Vachel Lindsay, he had only two daughters, Lady Sarah Elizabeth Russell, born on 16 January 1946, and Lady Lucy Catherine Russell (21 July 1948 - 11 April 1975), neither of whom married or bore children.

John Russell had a distinguished early career, working among other organisations for the FAO but in later life went insane and was diagnosed as 'schizophrenic'. This made him uniquely the only person in the UK denied the vote on two counts; one of being a peer and two of being mad. He made a speech to the House of Lords which was considered so outlandish that to this day it is the only speech unrecorded by Hansard.

Lord Russell was succeeded by his half-brother, the historian Conrad Russell, 5th Earl Russell.