The title of Viscount Mountgarret was created in the Peerage of Ireland in 1550. In 1794, the 12th Viscount was made Earl of Kilkenny, but this title became extinct with his death in 1846.
The Viscount bears the subsidiary titles of Baron Kells (1550) in the Peerage of Ireland and Baron Mountgarret (1911) in the Peerage of the United Kingdom, under which title the Viscounts sat in the House of Lords before 1999.
Viscounts Mountgarret (1550)
- Richard Butler, 1st Viscount Mountgarret (1500-1571)
- Edmund Butler, 2nd Viscount Mountgarret (d.1602)
- Richard Butler, 3rd Viscount Mountgarret (1578-1651)
- Edmund Butler, 4th Viscount Mountgarret (1595-1679)
- Richard Butler, 5th Viscount Mountgarret (d.1706)
- Edmund Butler, 6th Viscount Mountgarret (1663-1735)
- Richard Butler, 7th Viscount Mountgarret (1685-1736)
- James Butler, 8th Viscount Mountgarret (1686-1749)
- Edmund Butler, 9th Viscount Mountgarret (1687-1751)
- Edmund Butler, 10th Viscount Mountgarret (d.1779)
- Edmund Butler, 11th Viscount Mountgarret (1745-1793)
- Edmund Butler, 1st Earl of Kilkenny, 12th Viscount Mountgarret (1771-1846)
- Henry Edmund Butler, 13th Viscount Mountgarret (1816-1900)
- Henry Edmund Butler, 14th Viscount Mountgarret (1844-1912)
- Piers Henry Augustine Butler, 15th Viscount Mountgarret (1903-1966)
- Richard Henry Piers Butler, 16th Viscount Mountgarret (b. 1936)
