West will leave Franklin's Gardens at the conclusion of this campaign, bringing an 11-year association with Northampton to an end.
The former Leicester Tigers and England hooker was a long-time sidekick of Jim Mallinder, who was dismissed as director of rugby in December.
Together, Mallinder and West masterminded some of the most successful times in Saints history after helping the club return to England's top flight in 2008.
Saints won their first Premiership title in 2014 and also claimed two Challenge Cups and an Anglo-Welsh Cup.
West helped to build to most formidable forward pack in Europe during Saints' incredible run to the Heineken Cup final in 2011, when Leinster snatched glory in Cardiff.
And Saints CEO Mark Darbon said: "I would like to thank Dorian for everything he has done for Northampton Saints.
“We have been very lucky to have him at Franklin’s Gardens and he will always be a part of the Saints family.
“Dorian is a superb professional and is now firmly focused on helping the squad to finish the current season as strongly as possible.”
John White, Saints chairman, added: “Under Dorian’s guidance, the club possessed the most ferocious pack in English rugby and his role in our triumphs over the last decade should not be underestimated.
“Dorian leaves with our very best wishes and thanks for everything he has contributed to Saints.”