The list of by-elections in the United Kingdom is divided chronologically by parliament:

Parliament of England

• List of English by-elections (1689–1700)
• List of English by-elections (1701–1707)

Parliament of Great Britain

• List of Great Britain by-elections (1707–1715)
• List of Great Britain by-elections (1715–1734)
• List of Great Britain by-elections (1734–1754)
• List of Great Britain by-elections (1754–1774)
• List of Great Britain by-elections (1774–1790)
• List of Great Britain by-elections (1790–1800)

Parliament of the United Kingdom

• List of United Kingdom by-elections (1801–1806)
• List of United Kingdom by-elections (1806–1818)
• List of United Kingdom by-elections (1818–1832)
• List of United Kingdom by-elections (1832–1847)
• List of United Kingdom by-elections (1847–1857)
• List of United Kingdom by-elections (1857–1868)
• List of United Kingdom by-elections (1868–1885)
• List of United Kingdom by-elections (1885–1900)
• List of United Kingdom by-elections (1900–1918)
• List of United Kingdom by-elections (1918–1931)
• List of United Kingdom by-elections (1931–1950)
• List of United Kingdom by-elections (1950–1979)
• List of United Kingdom by-elections (1979–2010)
• List of United Kingdom by-elections (2010–present)
• By-elections to the House of Lords (hereditary peers)

Other parliaments

• List of by-elections to the Scottish Parliament
• List of by-elections to the Senedd
• List of European Parliament by-elections in the United Kingdom
• List of Northern Ireland Parliament by-elections (1921–1972)
• Northern Ireland Assembly vacancies are filled by co-option

Local government

Local government by-election results are generally given on the page for the last election in that area, see Category:Council elections in the United Kingdom