Alannah Joan Geraldine Cecilia MacTiernan (born 10 January 1953 in East Melbourne, Victoria) is an Australian politician. She was an Australian Labor Party member of the Western Australian Legislative Assembly from 1996 until 2010, and served as a senior minister in the Gallop state Labor government. She resigned from state politics in July 2010 in an unsuccessful attempt to win the federal seat of Canning at the 2010 federal election, served as mayor of the City of Vincent in local politics from 2011 to 2013, and was elected to the federal seat of Perth at the 2013 federal election.
Alannah MacTiernan studied at the University of Western Australia where she completed an arts degree and a law degree. She started her career with the federal government, in the area of Aboriginal employment and training. She was elected to the Perth City Council in 1988, where she remained until 1994. In 1993, she was elected as the member for the East Metropolitan region in the Western Australian Legislative Council.