Robert James Brown (born 27 December 1944) is a former Australian politician, medical doctor, and environmentalist who is a former Senator, and former Parliamentary Leader of the Australian Greens. Brown was elected to the Australian Senate on the Tasmanian Greens ticket, joining with sitting Greens Western Australia senator Dee Margetts to form the first group of Australian Greens senators following the 1996 federal election. He was re-elected in 2001 and in 2007. He was the first openly gay member of the Parliament of Australia, and the first openly gay leader of an Australian political party.
While serving in the Tasmanian parliament, Brown successfully campaigned for a large increase in the protected wilderness areas. Brown led the Australian Greens from the party's foundation in 1992 until April 2012, a period in which polls grew to around 10% at state and federal levels (13.9% of the primary vote in 2010). From 2002 to 2004, when minor parties held the balance of power in the Senate, Brown became a well-recognised politician. In October 2003 Brown was the subject of international media interest when he was suspended from the parliament for interjecting during an address by United States president George W. Bush.
On 13 April 2012, Brown resigned as leader of the Greens and indicated his intention to resign from the Senate in June. This occurred on 15 June 2012.