The 1921 Heywood and Radcliffe by-election was held on 8 July 1921. The by-election was held due to the elevation to the peerage of the incumbent Coalition Liberal MP, Albert Illingworth. It was won by the Labour candidate Walter Halls. 
|National Liberal||Abraham England||13,125||40.7||New|
|Labour gain from Liberal||Swing|
The Parliament of Northern Ireland was the home rule legislature of Northern Ireland, created under the Government of Ireland Act 1920, which sat from 7 June 1921 to 30 March 1972, when it was suspended because of its inability to restore order during The Troubles, resulting in the introduction of Direct Rule. It was abolished under the Northern Ireland Constitution Act 1973.
The 1922 United States House of Representatives elections were held for the United States House of Representatives in November 1922, in the middle of President Warren G. Harding's term. Just as voters had expressed their distrust of Wilson in 1920, now voters had a chance to express the widespread feeling that Congress had failed to address economic problems, especially the brief but sharp economic recession of 1921–1922. Most of the seats that Republicans lost had long been held by Democrats, who now returned with an even stronger base in the major cities.
The 1920 United States House of Representatives elections were held, coinciding with the election of President Warren G. Harding, the first time that women in all states were allowed to vote in federal elections after the passage of the 19th Amendment.
The 1926 Alberta general election was held on June 28, 1926, to elect members of the Legislative Assembly of Alberta. The writs of election were issued on May 10, 1926, allowing an election period of 40 days.
Early general elections were held in Sweden between 10 and 26 September 1921. In the first elections held under universal suffrage, the Swedish Social Democratic Party remained the largest party, winning 93 of the 230 seats in the Second Chamber of the Riksdag. Party leader Hjalmar Branting formed his second government.
The 1921 Louth by-election was a by-election held on 22 September 1921 for the British House of Commons constituency of Louth in Lincolnshire.
The 1921 Penrith and Cockermouth by-election was a parliamentary by-election held for the British House of Commons constituency of Penrith and Cockermouth in Cumberland on 13 May 1921.
Cochrane was a provincial electoral district in Alberta mandated to return a single member to the Legislative Assembly of Alberta from 1909 to 1926 under the First Past the Post voting system and under Single Transferable Vote from 1926 to 1940.
1921 The Orkney and Shetland by-election was a parliamentary by-election held for the British House of Commons constituency of Orkney and Shetland on 17 May 1921.
The 1921 Bedford by-election was a parliamentary by-election held for the House of Commons constituency of Bedford on 23 April 1921.
The 1921 South Londonderry by-election was held on 29 August 1921. The by-election was held due to the appointment as Lord Chief Justice of Northern Ireland of the incumbent UUP MP, Denis Henry. It was won unopposed by the UUP candidate Robert Chichester.
The 1921 Belfast Duncairn by-election was held on 23 June 1921. The by-election was held due to the incumbent Ulster Unionist MP, Edward Carson, being appointed Lord of Appeal in Ordinary. It was won by the UUP candidate Thomas Edward McConnell, who was unopposed. The seat was abolished in 1922.
The 1921 Bewdley by-election was held on 19 April 1921. The by-election was held due to the incumbent Coalition Conservative MP, Stanley Baldwin, being appointed President of the Board of Trade. It was retained by Baldwin.
The 1921 Kirkcaldy Burghs by-election was held on 4 March 1921. The by-election was held due to the resignation of the incumbent Coalition Liberal MP, Henry Dalziel. It was won by the Labour candidate Tom Kennedy.
The 1921 Dover by-election was held on 12 January 1921. The by-election was held due to the succession to the peerage of the incumbent Coalition Unionist MP, Vere Ponsonby as Ninth Earl of Bessborough. It was won by the Independent candidate Thomas Andrew Polson.
Elections were held in the state of Western Australia on 12 March 1921 to elect all 50 members to the Legislative Assembly. The incumbent government, led by Premier James Mitchell of the Nationalist Party and supported by the Country Party and National Labor Party, won a second term in government against the Labor Party opposition, led by Opposition Leader Philip Collier.
The 1921 San Diego mayoral election was held on April 5, 1921, to elect the mayor for San Diego. In the primary election, former mayor James E. Wadham and former City Councilmember John L. Bacon received the most votes and advanced to the runoff. Bacon was then elected mayor with a majority of the votes.
There was a single special election in 1921 to the United States Senate. It was held in New Mexico for the Class 2 seat, previously held by Albert B. Fall, who resigned March 3, 1921 to become U.S. Secretary of the Interior. Holm O. Bursum was appointed March 11, 1921 to replace him until this special election. On September 20, 1921 he also won the election.
United States gubernatorial elections were held in 1921, in two states.
The 1921 Pittsburgh mayoral election was held on Tuesday, November 8, 1921. Republican nominee William A. Magee was elected by a large margin over Democratic candidate William N. McNair.