By-elections to the 29th Alberta Legislature were held to fill vacancies in the Legislative Assembly of Alberta after the 2015 election. Two by-elections were held to fill vacancies in the 29th Alberta Legislature.
The 29th Alberta Legislature was formed after the 2015 election, during which the New Democrats won their first majority government under the leadership of Rachel Notley. Three by-elections were held in ridings which were initially won by the Progressive Conservatives, and these returned one Wildrose, one Progressive Conservative, and one United Conservative member each to the legislature. Two held in ridings initially won by Wildrose returned United Conservative members.