Thomas Butler, 6th Viscount Ikerrin (1683 – 7 March 1719) was an Irish nobleman, born in Kilkenny, Ireland to and , daughter of Colonel Daniel Redman, of Ballylinch, County Kilkenny and Abigail Otway. He was a descendant of John Butler of Clonamicklon. Thomas was a member of the clergy and Chaplain-General to the Army in Flanders. He married Margaret Hamilton, daughter and co-heiress of James Hamilton of Bangor, County Down and Sophia Mordaunt, daughter of John Mordaunt, 1st Viscount Mordaunt and Elizabeth Carey. His elder brother Pierce Butler, 4th Viscount Ikerrin, a Brigadier general in the Army, died in 1711, leaving an infant son, James, who succeeded as 5th Viscount but died young, whereupon Thomas succeeded to the title.