The Guinness family is an extensive aristocratic Anglo-Irish Protestant family noted for their accomplishments in brewing, banking, politics, and religious ministry. They are particularly known among the general public for producing the dry stout, Guinness Beer, which they still own to this day. The founder of the dynasty, Arthur Guinness, is believed to have had partly McCartan origins. Beginning in the late 18th century, they became a prominent part of what is known in Ireland as 'the Ascendancy'.
Four members of the family in succession held the UK Parliament constituency of Southend, which became popularly known as "Guinness-on-Sea".
The "banking line" Guinnesses all descend from Arthur's brother Samuel (1727–1795) who set up as a goldbeater in Dublin in 1750; his son Richard (1755–1830), a Dublin barrister; and Richard's son Robert Rundell Guinness who founded Guinness Mahon in 1836.