The second Johnson ministry began on 16 December 2019, three days after Boris Johnson's audience with Queen Elizabeth II where she invited him to form a new administration following the 2019 general election. The Conservative Party was returned to power with a majority of 80 seats in the House of Commons. Initially the ministers were largely identical to those at the end of the first Johnson ministry, but changed significantly in cabinet reshuffles in February 2020 and September 2021.

The first Johnson ministry began on 24 July 2019 when Queen Elizabeth II invited Boris Johnson to form a new administration, following the resignation of the predecessor Prime Minister Theresa May. May had resigned as Leader of the Conservative Party on 7 June 2019; Johnson was elected as her successor on 23 July 2019. The Johnson ministry was formed from the 57th Parliament of the United Kingdom, as a Conservative minority government. It lost its working majority on 3 September 2019 when Tory MP Phillip Lee crossed the floor to the Liberal Democrats. An election was called for 12 December 2019, which led to the formation of a Conservative majority government, the second Johnson ministry.