Brian David Mason is a Canadian politician who was leader of the Alberta New Democratic Party from 2004 to 2014 and served the Minister of Transportation in Rachel Notley's NDP government. He also served as the Government House Leader. Mason was first elected as a Member of the Legislative Assembly of Alberta for the now-defunct riding of Edmonton Highlands in a 2000 byelection. He was subsequently re-elected, and was elected in Edmonton-Highlands-Norwood after the riding was created in 2004. He chose not to seek re-election in 2019, and was succeeded by Janis Irwin. Mason was the longest serving NDP MLA in Alberta history, with a political career spanning more than 20 years.

The Alberta New Democratic Party, commonly shortened to Alberta NDP, is a social-democratic political party in Alberta, Canada. It is the provincial Alberta affiliate of the federal New Democratic Party, and the successor to the Alberta section of the Co-operative Commonwealth Federation and the even earlier Alberta wing of the Canadian Labour Party and the United Farmers of Alberta. From the mid-1980s to 2004, the party abbreviated its name as the "New Democrats" (ND).