Liberal senator and former minister Linda Reynolds will retire from politics at the next federal election.
The West Australian senator announced on Monday she would not be seeking pre-selection for another term.
"For 40 years I have proudly served my nation in the army, in the Liberal Party, in defence industry, in parliament and in government," she said.
"In my career after the Senate, I will continue to serve, but in new ways.
"My decision has been made after considerable reflection of what is behind me and the opportunities that are now ahead of me."
Senator Reynolds, who entered parliament in 2014 before being re-elected in 2016 and 2019, thanked party members for endorsing her on three separate occasions.
"I will, of course, keep working with my party to assist it to diversify and strengthen and do all I can to support the election of Peter Dutton as our next prime minister and Libby Mettam as WA’s next premier," she said.
Senator Reynolds was widely criticised for her response to rape allegations by former staff member Brittany Higgins.
She has since launched defamation action against Ms Higgins and her partner over social media posts in relation to the claims.
Prior to entering federal parliament, Senator Reynolds enlisted in the army reserves at the age of 19 and later became a Liberal staffer for Fred Chaney, Judi Moylan and Chris Ellison.