Thomas Woodcock CVO OStJ DL FSA (born 20 May 1951) is the Garter Principal King of Arms.
Woodcock was educated at Eton College. He went to University College, Durham, graduating with a Bachelor of Arts degree. He then went to Darwin College, Cambridge where he received his LLB degree. He was called to the Bar at the Inner Temple. In 1998, Woodcock married Lucinda Harmsworth King.
He began his heraldic career in 1975 as a research assistant to Sir Anthony Wagner, Garter King of Arms. In 1978 he was appointed Rouge Croix Pursuivant. In 1982 he was promoted to Somerset Herald. He held this office until his appointment as Norroy and Ulster in 1997. Woodcock was appointed the Garter Principal King of Arms on 1 April 2010.
Woodcock was appointed Lieutenant of the Royal Victorian Order (LVO) in the 1996 Birthday Honours and was advanced to Commander of the Royal Victorian Order (CVO) in the 2011 Birthday Honours. He was appointed Genealogist of the Most Venerable Order of the Hospital of Saint John of Jerusalem in June 2017 upon the retirement of the previous Genealogist, William Hunt as Windsor Herald, and made an Officer of the Order (OStJ) in July 2018.
In December 2005 he was appointed a deputy lieutenant for the County of Lancashire, in which capacity he assists the Lord Lieutenant, Lord Shuttleworth, to represent Queen Elizabeth II in the county.