Sir Thomas Fiennes, 8th Baron Dacre (1472 – 9 September 1534) was an English peer and soldier, the son of Sir John Fiennes.
He was born in 1472, the son of Sir John Fiennes and Alice FitzHugh. He had one sister, Anne, Marchioness Berkeley (died 10 September 1497). Thomas was invested as a Knight of the Bath in 1484 at the age of 12. On 8 March 1486, he succeeded as 8th Baron Dacre upon the death of his grandmother Joan Dacre, the suo jure 7th Baroness Dacre. He was also known as Baron Dacre of the South due to his family seat of Herstmonceux Castle being in the county of Sussex.
In 1493, one year after his marriage, he was appointed Constable of Calais. In 1497, he fought in the Battle of Blackheath where he helped defeat the Cornish.
In about 1492, he married Anne Bourchier, the daughter of Sir Humphrey Bourchier and Elizabeth Tilney. The marriage produced three children:
Sir Thomas Fiennes (died 26 October 1528), married in 1514, Jane Sutton, daughter of Edward Sutton, 2nd Baron Dudley, and Cicely Willoughby, by whom he had one son, Thomas Fiennes, 9th Baron Dacre.
Mary Fiennes (1495–1531), married Sir Henry Norris, by whom she had issue.
John Fiennes (b. 1497).
He died on 9 September 1534 at the age of 62. He was succeeded by his eldest grandson, Thomas Fiennes, 9th Baron Dacre, as his two sons had predeceased him.