Robert Ussher (1592–1642) was an Irish Protestant Provost of Trinity College, Dublin and Bishop of Kildare.
The youngest son of Henry Ussher, he was educated at Trinity College, Dublin, being made fellow in 1611, and graduating B.A. 1612, M.A. 1614, viceprovost 1615; B.D. 1621. He was prebendary of St. Audoen's, Dublin (1617); rector of Ardstraw (1617); prebendary of Dromaragh (1624); and rector of Lurgan (1629).
On the death in 1627 of Sir William Temple, there was a disputed election to the provostship. The senior fellows elected Joseph Mead, who declined; the junior fellows elected Ussher (14 April 1627), and he was sworn in the same day. He was set aside by royal letter in favour of William Bedell, who was sworn in on 16 August. On Bedell's promotion as Bishop of Kilmore, Ussher was again elected (3 October 1629), and sworn in 13 January 1630. He owed his appointment to a temperate letter in his favour by his cousin, James Ussher, to whom an appeal had been made.
He was an able preacher, he promoted the study of the Irish language, and he defended the charter rights of the college; but was considered too dovish. On 11 August 1634 he resigned the provostship on being appointed archdeacon of Meath. On 25 February 1635 he was consecrated Bishop of Kildare. He died at Panta Birsley, near Ellesmere, Shropshire, on 7 September 1642, and was buried at Doddleston Chapel, near Oswestry. He married Jane, eldest daughter of Francis Kynaston, of Panta Birsley, and left issue.