The Honourable Justice Peter Buchanan (11 October 1943 – 19 May 2014) was a judge of the Supreme Court of Victoria, the highest court in Victoria, a state of Australia. Buchanan was appointed a judge of the court on 27 October 1997; he retired in October 2013. At the time of his retirement, Buchanan was, and remains, the longest-serving member of the Court of Appeal. Buchanan died on 19 May 2014.