2026 Aberdeen South by-election

A by-election for the United Kingdom parliamentary constituency of Aberdeen South will be held on 18 June 2026 following the election of incumbent Scottish National Party (SNP) MP Stephen Flynn to the Scottish Parliament at the 2026 Scottish Parliament election.

The by-election will occur on the same day as parliamentary by-elections in Arbroath and Broughty Ferry and Makerfield. As per the Scottish Elections (Representation and Reform) Act 2025, which bars individuals from simultaneously holding both Holyrood and Westminster seats, Flynn resigned his House of Commons position on 14 May 2026.

Aberdeen South was created in the 19th century and was first contested at the 1885 general election. It contains southern areas in the city of Aberdeen, including the wards of George Street/Harbour, Lower Deeside, Hazlehead/Queens Cross/Countesswells, Airyhall/Broomhill/Garthdee, Torry/Ferryhill and Kincorth/Nigg/Cove.

The constituency's inhabitants are 86% ethnically White, with 67% categorised as social grades A, B and C1. The average household income is £35,675, below the average for Great Britain as a whole but above that for Scotland, and the home-ownership rate is 59%, lower than both the Scotland and Great Britain averages. In the 2016 referendum, 66% of those who voted in the constituency favoured remaining in the European Union.

Historically, Aberdeen South has been won by the Liberal, the Unionist and the Labour parties. Anne Begg from Labour was elected at the 1997 general election, defeating incumbent Conservative MP and government minister Raymond Robertson. She was re-elected in 2001, 2005 and 2010. At the 2015 general election, Begg lost her seat to SNP candidate Callum McCaig. In 2017, he lost his seat in a surprise result to the Conservatives. Stephen Flynn then defeated Ross Thomson in 2019. In the 2024 United Kingdom general election, Flynn was re-elected in Aberdeen South; it was one of only nine seats to elect an SNP candidate. Flynn had a majority of 3,758 votes. He returned as Leader of the Scottish National Party in the House of Commons. In the 2026 Scottish Parliament election he was elected MSP for Aberdeen Deeside and North Kincardine.

On 12 May, Douglas Lumsden, a Conservative MSP for North East Scotland recently re-elected to the Scottish Parliament, announced his intention to contest the Aberdeen South by-election, and he was officially selected as candidate by Aberdeen Conservatives on 15 May. He publicly urged Reform UK supporters to back him in a tactical vote. In the 2026 Scottish Parliament election, the Conservatives finished 1,244 votes behind the SNP in the overlapping seat of Aberdeen Deeside and North Kincardine, with Reform UK third. If Lumsden is elected to Westminster, James Adams will take his place as an MSP since he was next on the Scottish Conservative North East Scotland list (excluding Alexander Burnett who was re-elected in Aberdeenshire West).

On 22 May, the Scottish Greens announced Jorg Shelton-Eckstein as their candidate for the Aberdeen South by-election.

On 22 May, Scottish Labour announced Nurul Hoque Ali as its candidate for the by-election. He contested Gordon and Buchan at the 2024 United Kingdom general election, finishing fourth, and represents Bridge of Don ward on Aberdeen City Council.

On 18 May, Reform UK announced former nurse Jo Hart as its candidate. Hart had previously stood in the 2026 Scottish Parliament election for Aberdeenshire West, coming third behind the Conservatives and SNP. She also stood in the 2024 United Kingdom general election in Aberdeenshire North and Moray East, again coming third behind the SNP and Conservatives. Hart previously attracted controversy from past comments criticising the Royal Family, labelling them as "benefits scroungers", as well as for comments concerning 5G masts.

On 18 May, Richard Thomson, former MP for Gordon, announced his candidacy for the Aberdeen South by-election. Thomson served as MP for Gordon from 2019 until 2024, when he was defeated by Conservative Harriet Cross in the new constituency of Gordon and Buchan. Thomson unsuccessfully attempted to stand as an SNP candidate in the 2026 Scottish Parliamentary elections, seeking the nomination for Angus North and Mearns. On 20 May, Thomson was announced as the party's candidate for the by-election.

David Ballantine is the Alliance for Democracy and Freedom candidate. He came sixth in Hamilton, Larkhall and Stonehouse at the 2026 Scottish Parliament election and earlier stood in Edinburgh South West for the Brexit Party in the 2019 general election, again coming sixth.

On 22 May 2026, Kemi Badenoch visited Aberdeen to campaign with Douglas Lumsden.

• 2026 Arbroath and Broughty Ferry by-election (same day)
• 2026 Makerfield by-election (same day)
• List of United Kingdom by-elections (2010–present)