Joanne Kate Swinson CBE FRSA (born 5 February 1980) is a Scottish former politician who was Leader of the Liberal Democrats from July to December 2019. Swinson was Member of Parliament (MP) for East Dunbartonshire from 2005 to 2015 and 2017 to 2019. In September 2020, Swinson became Director of Partners for a New Economy (P4NE).

Swinson studied at the London School of Economics, and briefly worked in public relations, before being elected to the House of Commons aged 25, becoming the youngest MP at the time. She was a Liberal Democrat Spokesperson covering various portfolios, including Scotland, Women and Equalities, Communities and Local Government, and Foreign and Commonwealth Affairs.

In 2010, after the Liberal Democrats entered into a coalition government with the Conservative Party, Swinson was a Parliamentary Private Secretary to Deputy Prime Minister Nick Clegg, and was later appointed Parliamentary Under Secretary of State for Employment Relations and Postal Affairs. She lost her seat in the 2015 election, but regained it in the snap election held two years later. Shortly after returning to Parliament, she was elected unopposed as Deputy Leader of the Liberal Democrats. In July 2019, following the retirement of Vince Cable, Swinson defeated Ed Davey in a leadership election to become Leader of the Liberal Democrats.

Swinson led her party through the 2019 general election, suggesting she could lead a Liberal Democrat majority government which would revoke Article 50 and cancel Brexit. Instead, Swinson and the Liberal Democrats sustained a net loss in seats, including her own to the Scottish National Party and was disqualified from continuing as party leader. At less than five months, her tenure as leader was the shortest in the Liberal Democrats' history. She is also the only incumbent Liberal Democrat leader to have lost a Parliamentary seat.

Swinson was born in Glasgow on 5 February 1980, the daughter of Peter and Annette Swinson. She was educated at Douglas Academy, a mixed state school in the town of Milngavie in East Dunbartonshire in western Scotland, followed by the London School of Economics, where she studied Management, gaining a first-class Bachelor of Science degree in 2000. She signed up as an active member of the Liberal Democrats at the age of 17.

After graduating from the London School of Economics, Swinson moved to Yorkshire and worked for Ace Visual and Sound Systems in Thorne, before becoming a marketing and public relations manager for Hull-based commercial radio station Viking FM from December 2000, and media company Space and People.

At the age of 21, Swinson stood unsuccessfully in the Kingston upon Hull East constituency in the 2001 general election, but gained a 6% swing from John Prescott, then the Deputy Prime Minister of the United Kingdom. In 2003, she unsuccessfully contested Strathkelvin and Bearsden seat in the Scottish Parliament election, finishing third with 14% of the vote.

Swinson was elected to the House of Commons as the MP for East Dunbartonshire at the 2005 general election. She defeated John Lyons of Labour by 4,061 votes, and was the first ever Member of Parliament born in the 1980s. As the youngest MP she replaced fellow Lib Dem MP Sarah Teather as the "Baby of the House". This lasted until 2009, when Conservative MP Chloe Smith was elected at the Norwich North by-election.