John Mark Lancaster TD MP (born 12 May 1970) is a British Conservative Party politician. He was elected as Member of Parliament for the North East Milton Keynes constituency at the 2005 general election and held its successor seat, Milton Keynes North, at the 2010 general election. Initially appointed as the PPS to the Secretary of State for International Development. He was appointed a Lord Commissioner of Her Majesty's Treasury in September 2012. He was appointed Parliamentary Under-Secretary of State for Defence Personnel, and Veterans at the Ministry of Defence following the formation of the second Cameron ministry on 12 May 2015. He was reappointed by Theresa May on her becoming Prime Minister in June 2016 and had Reserves added to his portfolio, changing job title to Minister for Defence Veterans, Reserves and Personnel.
Lancaster was educated at Kimbolton School where his father Ronald Lancaster was chaplain. He graduated as a BSc in Business Studies from the University of Buckingham and MBA from the University of Exeter Business School. He was awarded an Honorary PhD from Buckingham in 2008.