The 49-year-old South African has spent three years with Gloucester, taking them to the final of the European Challenge Cup in his first season.
Director of rugby David Humphreys said: “In his three years at Gloucester, Johan transformed the way we play the game and his ‘play to inspire’ philosophy will leave a lasting impact from his time at the club.”
Ackermann said working as head coach at Gloucester had been a “tremendous privilege”.
“Working with such a fantastic group of players and coaches has been a great experience,” he added.
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