Scott Johnson will leave his post as Scotland's director of rugby to move to a similar post with Australia next year.
The Scottish Rugby Union announced it had agreed a compensation deal with its Australian counterpart for Johnson to move after the Six Nations.
The 56 year old former Australia assistant coach began his role in 2013 after a spell as Scotland interim head coach.
"This has been a big decision but for me, right now, it is the right one to make. From the outset I've wanted to make Scotland more competitive on the world stage on all levels," said Johnson.
"I've had the opportunity to work with some highly talented and committed people and together I think we have made progress in those areas and hope that will continue in the years ahead.
"I've loved my time in Scotland and I'd like to thank (SRU chief executive) Mark Dodson and the board for their support throughout.
"I won't be leaving Scottish rugby until after the Six Nations, where I'm looking forward to see how all our teams perform. It's been a great six years and I've enjoyed the challenge."
The move sees Johnson return to the Wallabies setup, after occupying the attack coach role in 2007, and comes bout as Rugby Australia restructure in response to the nation's worst year of Test rugby in the professional era.
Dodson added: "Scott has made a significant contribution to the development of elite rugby in Scotland and he leaves with our heartfelt thanks and appreciation for the work he has done.
"His unrivalled global rugby knowledge and connections at every level of the game have hugely benefited the development of how our game in Scotland has progressed in recent years, be that working with head coaches, forming partnerships beyond our borders and establishing Scottish Rugby's high performance department to the level it is today.
"He leaves with our best wishes for the next stage of his career."
