The Alberta Liberal Party is a provincial political party in Alberta, Canada. Founded in 1905, it is the oldest active political party in Alberta and was the dominant political party until the 1921 election, with the first three provincial Premiers being Liberals. Since 1921, it has formed the official opposition in the Legislative Assembly of Alberta several times, most recently from 1993 until 2012. Fourteen Liberals have served as Leader of the Opposition of Alberta.

The leader of the Official Opposition, formally known as the leader of His Majesty's Loyal Opposition, is the member of the Legislative Assembly (MLA) who leads the Official Opposition, typically the second largest party in the provincial legislature.