The former Highlanders' first five-eighth said he believed it was the right decision "for himself and the team to make the change ahead of next year's Rugby World Cup in England."
The Black Ferns played eight tests this year winning, winning only four of them.
They had wins over the USA, Australia and France, but lost to England twice, along with Ireland and Canada.
"The 2024 season was challenging for the group with mixed performances on the field, but also for myself personally juggling family. A World Cup year needs total commitment to give the team the best chance to defend their title, with that in mind, I've made a pretty tough call to step aside," Delany said.
Black Ferns director of rugby Allan Bunting acknowledged Delany's contribution to the team.
"Mike's a quality coach and person, and the passion and care he's brought to the environment over the past two seasons has been significant. He has a breadth of knowledge and his honesty and input to the group will be valuable as we look toward 2025."
Delany's long playing career included one test for the All Blacks in 2009, as well as 19 matches for the Highlanders in two separate stints in 2008 and 2012.
