Henry Denne (1606?-1660) was a Church of England clergyman and controversialist, later a prominent Baptist.
He is identified as the son of David Denne of Kent, educated at Latton, Essex under his uncle, Thomas Denne. He matriculated as a sizar at Sidney Sussex College, Cambridge in 1621, graduating B.A. in 1625 and M.A. 1628. In 1630 he was ordained by Theophilus Feild, Bishop of St David's, and soon afterwards became curate of Pirton, Hertfordshire, a preaching position he held for more than ten years.
In 1641 he was one of the ministers selected by the committee of the House of Commons for preferment; in the same year he preached at Baldock at the visitation held there, giving offence by attacking the vices of the clergy. This sermon was subsequently published as "The Doctrine and Conversation of John Baptist" (1642). Soon after the outbreak of the First English Civil War Denne became convinced of the unscriptural nature of the baptism of infants, and publicly professing himself a baptist was received by immersion in 1643, when he joined the congregation at the meeting-house in Bell Alley, London and helped to lead it along with Thomas Lambe and Samuel Oates. He frequently preached both there and in the country.
His change of opinion brought persecution, and in 1644 he was apprehended in Cambridgeshire, by order of the "committee" for that county, for preaching against infant baptism. After he had lain in Cambridge gaol for some time, his case, through the intercession of some friends, was referred to a committee of the House, and he was sent to London, where he was confined in Lord Petre's house in Aldersgate Street until, his case having been investigated, the committee ordered his release. Among his fellow-prisoners was Dr Daniel Featley, the opponent of the baptists, whose book, The Dippers Dipt was brought to Denne's notice. As soon as he was released he challenged Featley to a disputation. Featley, pleading the danger of publicly disputing without a licence, declined to continue with it. Denne then wrote The Foundation of Children's Baptism discovered and rased; an answer to Dr Featley, &c. (1645), which was for a time a standard authority among the baptists.