Dorian West says Jim Mallinder's departure has meant he has 'gradually come to the decision' to leave Saints this summer.
Mallinder was dismissed from his role as Saints director of rugby in December, and Hurricanes head coach Chris Boyd will be taking over this summer.
Boyd has met with West, but they have come to the mutual decision that it is time for the club to appoint a new forwards coach.
West was a key part of Mallinder's coaching team since the pair took over at Franklin's Gardens in the summer of 2007.
They helped to take Saints back into England's top flight after an unbeaten season in the second tier before masterminding a Challenge Cup success in 2009.
Saints went on to win the Anglo-Welsh Cup in 2010, beating Gloucester in the final, before a sensational run to the 2011 Champions Cup final.
They were eventually beaten by Leinster in Cardiff, but Saints' forward pack had become one of the most formidable in Europe and West's reputation was at its peak.
Saints then claimed their first Premiership title in 2014, along with another Challenge Cup crown.
And West said: “I’ve created some fantastic memories at Franklin’s Gardens, and I want to thank Jim Mallinder and all the staff for their support and friendship in my time here.
“I’m very proud of what I’ve achieved at Saints; we turned a side that had just been relegated from the Premiership into one of the very best teams in Europe.
“When you look back on your career as a player or a coach, you remember the trophies you won rather than the games you lost, and I’m happy we were able to win so many finals for the people of Northampton over the last decade.
“But all good things must come to an end and after Jim left the club earlier in the season I have gradually come to the decision that it’s time for a new challenge away from Franklin’s Gardens.
“I wish the playing squad all the best for the future, and for now I hope we can end this season on a high note.”
Saints have endured some tough times during the past few seasons and currently sit 10th in the Aviva Premiership.
The search for a new forwards coach is already under way.