| Honorific-Prefix: | The Right Honourable |
| The Lord Ashton of Hyde | |
| Office: | Master of the Horse |
| Term Start: | 18 June 2024 |
| Predecessor: | The Lord de Mauley |
| Office1: | Chair of the International Relations and Defence Committee |
| Predecessor1: | The Baroness Anelay of St Johns |
| Term Start1: | 31 January 2023 |
| Office2: | Chief Whip of the House of Lords Captain of the Honourable Corps of Gentlemen-at-Arms |
| Primeminister2: | Boris Johnson |
| Term Start2: | 26 July 2019 |
| Term End2: | 7 September 2022 |
| Predecessor2: | The Lord Taylor of Holbeach |
| Successor2: | The Baroness Williams of Trafford |
| Office3: | Parliamentary Under-Secretary of State for Civil Society |
| Primeminister3: | Theresa May |
| Term Start3: | 13 July 2016 |
| Term End3: | 26 July 2019[1] |
| Predecessor3: | Rob Wilson |
| Successor3: | The Baroness Barran |
| Office4: | Lord-in-waiting Government Whip |
| Primeminister4: | David Cameron Theresa May |
| Term Start4: | 15 July 2014 |
| Term End4: | 11 June 2017 |
| Predecessor4: | The Lord Bates |
| Successor4: | The Lord Henley |
| Office5: | Member of the House of Lords |
| Status5: | Lord Temporal |
| Term Label5: | as an elected hereditary peer |
| Term Start5: | 25 July 2011 |
| Predecessor5: | The 7th Earl of Onslow |
| Birth Date: | 18 July 1958 |
| Party: | Conservative |
| Spouse: | Emma Allinson |
| Relatives: | Thomas Ashton (father) |
| Education: | Trinity College, Oxford (BA) |
Thomas Henry Ashton, 4th Baron Ashton of Hyde, (born 18 July 1958), is a British life peer and former insurance broker who served as Chief Whip of the House of Lords and Captain of the Honourable Corps of Gentlemen-at-Arms from 2019 to 2022. He succeeded to his family's peerage title on 2 August 2008.
Henry Ashton went to Eton College and Trinity College, Oxford. He was commissioned in the Royal Hussars, later becoming a Lieutenant in the Royal Wessex Yeomanry. Ashton worked as an insurance broker and held the position of Chief Executive Officer at Berkshire Hathaway-owned Lloyd's firms Faraday Underwriting Ltd, and Faraday Reinsurance Co. Ltd, from 2005 until 2013. From 2010 to 2013 Lord Ashton was a member of the Council of Lloyd's.
Elected a representative hereditary peer in July 2011, Ashton sits in the House of Lords as a Conservative.[2] In the July 2014 government reshuffle he was appointed a Lord-in-waiting and Whip in the Lords by Prime Minister David Cameron,[3] serving until the 2017 general election.[4] In July 2016 Prime Minister Theresa May appointed him as Parliamentary Under-Secretary of State for the Department for Culture, Media & Sport.
In March 2019, Lord Ashton received international publicity and acclaim for giving a correct and clever definition[5] to Lord Geddes, to the latter's question about the meaning of the term algorithm. Lord Ashton gave the definition as "an algorithm is a set of rules that precisely defines a sequence of operations".[6] The definition was said to "[rival] dictionary entries for clarity and succinctness—wrapped up in a historical allusion that he knew his classically educated interlocutor would understand."[7]
In July 2019, Lord Ashton of Hyde was appointed Chief Whip in the House of Lords by new Prime Minister Boris Johnson.[8] He was appointed to the Privy Council the following month.[9]
In June 2024, Lord Ashton of Hyde was appointed Master of the Horse by King Charles III.
Descended from a cadet branch of the ancient Lancashire Assheton family, he married Emma Louise Allinson, daughter of Colin Allinson and Alison Palmer (née Bartholomew), in 1987; they have four daughters/
As he does not have any sons, the heir presumptive to the family title is his younger brother, Jack Ashton.[10]