John Downame (Downham) (1571–1652) was an English clergyman and theologian in London, who came to prominence in the 1640s, when he worked closely with the Westminster Assembly. He is now remembered for his writings.
He was the younger son of William Downham, bishop of Chester, and younger brother of George Downame. He was born in Chester, and received his education at The King's School, Chester and Christ's College, Cambridge, as a member of which he subsequently proceeded B.D. On 4 August 1599 he was instituted to the vicarage of St. Olave, Jewry, which he exchanged, 5 March 1601, for the rectory of St. Margaret, Lothbury, then recently vacated by his brother George, but resigned in June 1618. He would seem to have lived unbeneficed until 30 November 1630, when he became rector of Allhallows the Great, Thames Street, a living he held till his death. He was the first, says Thomas Fuller, who preached the Tuesday lectures in St. Bartholomew's Church behind the Exchange.
In 1640 he combined with ministers of the city (Cornelius Burgess, Edmund Calamy, John Goodwin and Arthur Jackson) in presenting a petition to the privy council against William Laud's innovative book of canons. In 1643 he was appointed one of the licensers of the press, granting imprimatur to theological works, a role in which he took a permissive line, one of the works he approved being Judgement of Martin Bucer Concerning Divorce by John Milton; his licensing of Eikon Basilike in 1649 attracted the attention of the Council of State. In 1644 he was chosen one of the London ministers to examine and ordain public preachers.