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 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.

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.