| The Earl of Bessborough | |
| Noble Family: | Ponsonby |
| Birth Date: | 1679 |
| Death Date: | 4 July 1758 (age 78–79) |
| Occupation: | Politician, peer |
| Father: | William Ponsonby, 1st Viscount Duncannon |
| Mother: | Mary Moore |
Brabazon Ponsonby, 1st Earl of Bessborough (1679 – 4 July 1758), was a British politician and peer. He was the son of William Ponsonby, 1st Viscount Duncannon, and Mary Moore. He was an active politician from 1705 to 1757 in Great Britain and Ireland. He represented Newtownards and County Kildare in the Irish House of Commons. He inherited his father's viscountcy in 1724 and was made Earl of Bessborough in the Peerage of Ireland in 1739. He is buried in Fiddown, County Kilkenny, Ireland.
Ponsonby married Sarah Margetson, an heiress whose family owned Bishopscourt, County Kildare, and his family remained there until the 1830s.
Ponsonby married twice. His first marriage was in 1704 to Sarah Margetson (d. 21 May 1733), daughter of John Margetson and Alice Caulfeild, and granddaughter of James Margetson, Archbishop of Armagh. Sarah had previously been married to Hugh Colville, son of Sir Robert Colville of Newtownards and his third wife Rose Leslie. Sarah's children by Brabazon Ponsonby:
Following his wife's death in May 1733, Ponsonby married Elizabeth Sankey (circa 1680 – 17 July 1738), daughter of John Sankey and Eleanor Morgan, on 28 November 1733.