John Kennedy, 5th Earl of Cassilis (1575 – 14 November 1615) was a Scottish peer, the son of Gilbert Kennedy, 4th Earl of Cassilis and Margaret Lyon.
He succeeded to the titles of 7th Lord Kennedy and 5th Earl of Cassillis on 14 December 1576.
In 1596 Kennedy travelled in France and Italy and wrote to Archibald Douglas from Venice.[1]
He was one of the central figures in The Historie of the Kennedyis, an anonymous account of the feud between the Cassilis and Bargany Kennedy families published in 1830 by Robert Pitcairn. This feud climaxed in a pitched battle in December 1601, in which the Earl's men fatally wounded the Laird of Bargany who was returning home from Ayr. According to the Historie, the Earl also summarily hung a young man named Dalrymple, to whom he was related, for being a closer relation of Bargany's. In most of these deeds he was heavily influenced by his Tutor Thomas Kennedy of Culzean, which led to the murder of Culzean, by Bargany's younger brother, Thomas Kennedy of Drummurchie at Greenan Castle on 12 May 1602.
He held the office of Treasurer of Scotland on 22 March 1598/99.