Ann Vanstone KC is an Australian lawyer. She was a crown prosecutor before being appointed as a judge of the District Court of South Australia from 1999 until 2003. She was then appointed to the Supreme Court of South Australia. Vanstone stepped down from the Supreme Court bench in June 2019. On 27 July 2020, Vanstone was announced as the next South Australian Independent Commissioner Against Corruption, to take up the position on 1 September 2020.