Sir Thomas Wriothesley (/ˈraɪəθsli/REYE-əths-lee; died 24 November 1534) was a long serving officer of arms at the College of Arms in London. He was the son of Garter King of Arms, John Writhe, and he succeeded his father in this office.
Wriothesley was born at Colatford Wiltshire. His name at birth was Thomas Writhe, and he was the eldest son and second of four children of John Writhe and his first wife, Barbara, daughter of John Castlecombe. The location of Colatford has not been identified, but it was either near Castle Combe or Cricklade.
Wriothesley's first wife, whom he married before 1500, was Jane, daughter of William Hall of Salisbury. The pair had ten children together, though their only surviving son was Charles Wriothesley, Windsor Herald of Arms in Ordinary. His second wife was Anne, widow of Robert Warcop with whom he had a daughter who died in infancy. Wriothesley died "worn out with age" in London, on 24 November 1534, and was presumably buried with his family in St Giles Cripplegate. His will has never been found. His library may have stayed intact until the death of his son Charles in 1562; after that it was probably dispersed. Manuscripts of his are now to be found in the College of Arms, the British Library, and elsewhere.
In 1489 Wriothesley was made Wallingford Pursuivant in the private service of Prince Arthur at Wallingford and continued as such under Prince Henry. In 1491 he accompanied King Henry VII to Brittany. On 26 January 1505 he was appointed Garter King of Arms, over the heads of all the royal heralds in ordinary. Clarenceux King of Arms, Roger Machado, was an old friend of Wriothesley's father and helped push the appointment through. It was around this time that Thomas changed his original surname of Writhe to the grander one of Wriothesley, which he applied retrospectively to his ancestors. His brother William, York Herald of Arms in Ordinary joined him in this change.