Michael O'Brien (born 10 April 1949) was the Labor member for Napier in the South Australian House of Assembly from 2002 to 2014. He was Minister for Finance, Minister for Police, Minister for Emergency Services, Minister for Correctional Services and Minister for Road Safety. O'Brien was elevated to Cabinet on 2 March 2009 with Tom Koutsantonis following the resignations of Rory McEwen and Carmel Zollo. He resigned from Cabinet on 31 January 2014, at which time he also announced that he would not contest the 2014 South Australian election.