Thomas Taylour, 1st Marquess of Headfort

The Most Honourable The Marquess of Headfort KP
Portrait by Pompeo Batoni of Thomas Taylour, 1st Marquess of Headfort (1782), Museum of Fine Arts, Houston
Personal details
Spouse(s)	Mary Quin
Parents	Thomas Taylour, 1st Earl of Bective Jane Rowley

Thomas Taylour, 1st Marquess of Headfort KP (18 November 1757 – 24 October 1829), styled Viscount Headford from 1766 to 1795, and known as The Earl of Bective from 1795 to 1800, was an Irish peer and politician.

He was the son of Thomas Taylour, 1st Earl of Bective, whom he succeeded in 1795. The 1st Marquess of Headfort was married to Mary Quin, the daughter of George Quin and Caroline Cavendish and the granddaughter of Valentine Quin and Mary Widenham. Valentine Quin was the son of the 1st Earl of Dunraven and Mount-Earl (1752–1824), who was also 1st Viscount Mount-Earl, and whose son Lord George Quin married Lady Georgiana Charlotte, the daughter of George Spencer, 2nd Earl Spencer.

Headfort's elopement in 1803 with the wife of Reverend C. D. Massey produced a lawsuit, 10,000 pounds damages and, for the plaintiff, one of John Philpot Curran's most famous speeches.

Taylour represented Kells in the Irish House of Commons from 1776 to 1790. Subsequently he sat as Member of Parliament for Longford Borough until 1794 and then for Meath until 1795, when he succeeded his father as earl. He became Marquess of Headfort in 1800 and was appointed a Knight of the Order of St Patrick on 15 May 1806.