Barnaby Thomas Gerard Joyce (born 17 April 1967) is an Australian politician. He served as the leader of the National Party from February 2016 to February 2018, and was Deputy Prime Minister of Australia from February 2016 to October 2017 and from December 2017 to February 2018.

Joyce was born in Tamworth, New South Wales, and is a graduate of the University of New England. In 1999, he set up an accountancy practice in St George, Queensland.[3] Joyce was elected to the Senate at the 2004 federal election, taking office in 2005, though it subsequently emerged in 2017 that he was not eligible for election. He became the National Party's Senate leader in 2008.[4] At the 2013 election, he transferred to the House of Representatives, winning the rural seat of New England in New South Wales.

During 2013, Joyce replaced Nigel Scullion as deputy leader of the National Party. He succeeded Warren Truss as party leader and deputy prime minister in 2016. In the Abbott and Turnbull Governments, Joyce served as Minister for Agriculture (2013-2015), Minister for Agriculture and Water Resources (2015-2017), Minister for Resources and Northern Australia (2017) and Minister for Infrastructure and Transport (2017-2018).

During the 2017 parliamentary eligibility crisis, Joyce was confirmed to be a dual citizen of New Zealand.[5][6] On 27 October 2017, the High Court of Australia ruled that he had been ineligible to be a candidate for the House of Representatives at the time of the 2016 election.[6] Joyce re-entered parliament in December 2017 after winning the New England by-election with a large swing against low-profile opposition.[7] In February 2018, he resigned his ministerial and leadership roles after acknowledging that he was in a relationship and expecting a child with a former staffer. He was succeeded by Michael McCormack.[8]