Christian Day and Ken Pisi are among a group of 11 players who have signed new deals at Saints.
Centres Luther Burrell, Rory Hutchinson and Tom Stephenson have also put pen to paper on fresh contracts.
JP Estelles, who enjoyed a successful three-month trial before signing a deal until the end of this season, will now extend his stay into next season.
Ben Nutley and Tom Kessell are also sticking around, as are young hookers Charlie Clare and Reece Marshall, and lock Jordan Onojaife.
And Saints boss Jim Mallinder is delighted to have tied the players to new deals at Franklin’s Gardens.
“We’re delighted to have agreed these new contracts,” Mallinder said.
“Some of these players have been core members of the most successful period in the Saints’ history and we believe that they have a lot to offer both in terms of their play on the pitch and leadership qualities.
“It’s also fantastic to have a very good group of younger players who have come through the Saints Academy and are now members of the first-team squad.
“It’s important that we produce our own home-grown players who are able to compete for starting places alongside more experienced internationals, a combination which has been successful for us in the past.
“To compete at the highest level of the competitions we play in we need a squad that has a lot of quality and strength in depth and all of these players are important members of the group we have at Franklin’s Gardens.”