Catherine Esther Doust (born 27 May 1962) is an Australian politician who has been a Labor Party member of the Legislative Council of Western Australia since 2001, representing South Metropolitan Region.

Doust was born in Kalgoorlie and attended the University of Western Australia, graduating with a Bachelor of Arts degree.

From 1984, she worked as an official with the Shop, Distributive and Allied Employees Association, including as a board member and treasurer for periods.

[1] Doust entered parliament at the 2001 state election, standing in the second position on Labor's ticket in South Metropolitan Region.

[3] Doust was controversially replaced on 24 May 2021 due to long standing disagreements with Premier Mark McGowan particularly regarding a corruption probe into former Liberal MP Phil Edman.