Matthew John Birney (born 10 June 1969) was an Australian politician. He was a Liberal member of the Western Australian Legislative Assembly from 2001 to 2008, serving as Leader of the Opposition from 2005 to 2006. Birney was born in Sydney but comes from a family long established on the Western Australian goldfields, and has lived in the regional city of Kalgoorlie since childhood. His father, Jack Birney, was a Liberal member of the Australian House of Representatives from 1975 until his defeat in 1983. As of April 2019, his return to state politics did not eventuate.