Andrew John Julian Bartlett is an Australian politician, social worker, academic, and social campaigner who served as a Senator for Queensland from 1997 to 2008 and from 2017 to 2018. He represented the Australian Democrats in his first stint in the Senate, including as party leader from 2002 to 2004 and deputy leader from 2004 to 2008. In November 2017, he returned to the Senate as a member of the Australian Greens, replacing Larissa Waters after her disqualification during the parliamentary eligibility crisis. He resigned from the Senate in August 2018 in an unsuccessful attempt to win the House of Representatives seat of Brisbane, allowing Waters to fill his seat in advance of the 2019 election.

The Australian Democrats is a centrist political party in Australia. Founded in 1977 from a merger of the Australia Party and the New Liberal Movement, both of which were descended from Liberal Party dissenting splinter groups, it was Australia's largest minor party from its formation in 1977 through to 2004 and frequently held the balance of power in the Senate during that time.