Colonel Sir Horace Beauchamp Seymour KCH (22 November 1791 – 23 November 1851) was a Peelite Member of Parliament for Lisburn 1819–26, Orford (1820), Bodmin (1826–32), Midhurst (1841–45), Antrim (1845–47), and Lisburn 1847–51. He was an ancestor of Diana, Princess of Wales.
Horace Seymour was the son of Admiral Lord Hugh Seymour (son of Francis Seymour-Conway, 1st Marquess of Hertford) and Lady Anne Horatia Waldegrave. He married, firstly, Elizabeth Malet Palk, daughter of Sir Lawrence Palk, 2nd Baronet and granddaughter of Robert Palk, on 15 May 1818. He married, secondly, Frances Selina Isabella Poyntz, daughter of William Stephen Poyntz and Hon. Elizabeth Mary Browne, in July 1835.
By his first wife he had three children;