The twice capped England international possesses a wealth of first class experience and will add to Gloucester's front row options next season with the likes of Darren Dawidiuk and Huia Edmonds already on board.
Having started his career at Bath Rugby, he has since gone on to represent Munster, Rotherham, Newcastle Falcons and Northampton Saints.
His stay at Franklin's Gardens has seen him win an LV= Cup winners medal and anchor the Saints set piece in the absence of skipper Dylan Hartley.
As well as representing his country, the Poole born player is also closing in on 200 Premiership appearances - a significant achievement.
Despite all he has achieved in his career, Long admitted that the prospect of playing at Kingsholm for Gloucester is an exciting one.
"I've been fortunate enough to play for some great clubs in my time, but I have to admit that I'm really looking forward to joining Gloucester and playing in front of one of the most passionate crowds in rugby.
"I've always relished playing there and have experienced some great battles in front of the Shed.
"Gloucester have made some great signings for next season and I'm looking forward to playing my part in what should be an exciting season.
"In the meantime, however, I've still got work to do for the Saints and am 100% committed to that. The club have been great to me and I've enjoyed my time there."
Gloucester Rugby's Forwards Coach Carl Hogg explained that Long will bring plenty of qualities to the squad:
"We're absolutely delighted with Andy's arrival here next season. We've got some young front rowers and Andy's experience will be key there.
"He's got vast experience across the Premiership and is also a very good set piece technician and will fit in very nicely with our group.
"He's an outstanding professional and a very good role model and we're looking forward to having him on board."