Robert Andrew Simms (born 26 March 1984) is an Australian politician. He was a Greens member of the Senate, representing the state of South Australia, from 22 September 2015 until his defeat at the 2016 election. Until the appointment of James Paterson to the Senate in March 2016, he was the youngest serving senator and the second-youngest sitting MP (after Wyatt Roy).
Elected as a City of Adelaide councillor in 2014, he resigned on 8 September 2015 following the resignation of Penny Wright from the Senate, and was appointed to fill the casual vacancy that resulted.
Simms has worked in the community sector as a policy advocate, served on the boards of a number of community organisations including the Youth Affairs Council and AIDS Council of South Australia, and worked briefly as a radio journalist. He is also a freelance writer and resides in Adelaide.
He holds a Bachelor of Laws and Legal Practice (Honours), a Bachelor of Arts (majoring in politics and sociology) and a Graduate Certificate in Journalism. In 2008 he was admitted to the Supreme Court as a Barrister and Solicitor. As of 2015 Simms is partway through a PhD in political philosophy at Flinders University where he has also taught in the politics department.
Previously, Simms stood as a candidate for the Greens in Enfield at the 2010 state election, and the Electoral district of Adelaide in the 2014 state election. In 2015 he was a co-convenor of the SA Greens. He will be the Greens' candidate for Adelaide again at the 2018 state election.
As a senator, Simms was the Greens parliamentary spokesperson on higher education, LGBT rights and marriage equality—portfolios previously held by Senators Lee Rhiannon and Janet Rice.
Simms was one of five openly-LGBTI members in the Parliament of Australia and supports marriage equality in Australia.