Justin Thomas Gleeson SC (born 9 April 1961[1]) is an Australian lawyer and former Solicitor-General of Australia,[2] the Commonwealth's second-ranking law officer.

[2] Gleeson was appointed Solicitor-General in 2012, having acted in that capacity since the departure of Stephen Gageler the previous year.

[7] In addition to acting as counsel in domestic courts, Gleeson is also currently working as an international arbitrator.

[7] In September 2017, Gleeson joined the legal team of Tony Windsor, led by Ron Merkel QC, in the High Court case Re: Joyce, one of the seven cases constituting the 2017 Australian constitutional crisis.

His father is Gerald Gleeson AC, a former senior public servant in the Labor Government in New South Wales.