Stewart James Jackson, Baron Jackson of Peterborough (born 31 January 1965) is a British politician and adviser. Jackson served as a Conservative Member of Parliament (MP) for Peterborough from 2005 to 2017. After being ousted by Labour's Fiona Onasanya at the 2017 general election, he served as Chief of Staff, and Special Adviser to David Davis, Secretary of State for Exiting the European Union, until July 2018 when Davis resigned his position. He was made a member of the House of Lords as a life peer in November 2022.

Jackson was born in Woolwich, London, England, and was brought up in south-east London. He was educated at the London Nautical School, an all-boys comprehensive school in Lambeth, and Chatham House Grammar School, an all boys grammar school in Ramsgate, Kent. He then studied economics and public administration at Royal Holloway, University of London, graduating with a Bachelor of Arts (BA) degree in 1988. He was elected president of the University of London Union for the 1988–89 academic year. During his tenure as president, he faced a no-confidence motion in January 1989, and resigned before he was required to leave office. He later undertook a Master of Arts (MA) degree in human resource management at Thames Valley University.

Jackson served on Ealing Borough Council in west London from 1990 to 1998, during which time he was Conservative Party spokesman on planning and housing. He is Vice-President of the Local Government Association.

Jackson unsuccessfully contested the parliamentary constituency of Brent South at the 1997 general election. He was then selected as the Conservative candidate for the Peterborough seat in October 2000, and fought the 2001 general election, where he reduced the Labour Party's majority in the constituency from 7,323 votes to 2,854 votes, but lost to the incumbent Labour MP Helen Brinton. Jackson was re-adopted as the Conservative candidate for Peterborough in August 2002, and defeated Brinton at the 2005 general election to become the MP.

In the 2010 general election, held on 6 May, Jackson increased his majority to 4,861 votes over the Labour candidate, Ed Murphy; he was appointed the following month as Parliamentary private secretary (PPS) to Owen Paterson, the Secretary of State for Northern Ireland, but resigned as PPS on 24 October 2011, after voting against a three-line whip on an EU referendum.

Following Theresa May's selection as the new Conservative Prime Minister, following David Cameron's resignation, Stewart Jackson was appointed as Parliamentary Private Secretary to David Davis, the Secretary of State for Exiting the European Union, in July 2016.

Following the loss of his seat at the 2017 general election, Jackson was appointed Special Advisor and Chief of Staff to the Secretary of State at the Department for Exiting the European Union. On 25 April 2022 Stewart Jackson was appointed to the role of High Speed 2 Residents' Commissioner.

It was announced on 14 October 2022, that as part of Boris Johnson's 2022 Political Honours, Jackson would be appointed a life peer. On 16 November 2022, Jackson was created Baron Jackson of Peterborough, of Peterborough in the County of Cambridgeshire.