This is a list of by-elections to the Senedd (Welsh Parliament; ; formerly known as the National Assembly for Wales).
:''Where seats changed political party at the by-election, the result is highlighted.''
''*Peter Law left the Labour Party and sat as an independent prior to his death. The by-election was won by his widow, but is classed as an independent gain from Labour.''
See also
* List of by-elections to the Scottish Parliament
* Regional member changes to the Senedd
References
{{UK by-elections
Lists of by-elections in the United Kingdom, Senedd
By-elections to the Senedd, *
Wales politics-related lists, By