The Leader of the Opposition in the Senate is a party office held by the Opposition's most senior member of the Shadow Cabinet in the Australian Senate, elected to lead the opposition party (or parties) in the body.

[1] In addition to his or her own shadow ministerial portfolio, the leader has overarching responsibility for all policy areas and acts as the opposition's principal spokesperson in the upper house.

Another similarity is that the leader typically announces changes to opposition officeholders in the Senate, including shadow ministers, party leadership and whips.

[2] The leader also has some responsibility for appointing opposition senators to committees, a role filled by the Manager of Opposition Business and whips in the lower house.

The current leader is Michaelia Cash, assisted by a Deputy Leader of the Opposition in the Senate, currently Anne Ruston.