Props Alex Clarke and Darren Crompton and full-back or centre Josh Taumalolo have all signed new deals at the Memorial Ground.
The trio follow Mark Regan and Roy Winters, who have also recently pledged their futures to the club.
Clarke, who has overcome shoulder surgery to win a regular place in the side this season, has signed for a further three years.
Crompton, who is in his second spell at Bristol, has agreed a one-year extension to the end of next season while Taumalolo will stay for a further two years. Taumalolo joined the club from Neath this year.
Head coach Richard Hill said: "I'm absolutely delighted and it's a real statement of our intent to become a force in English and ultimately European rugby for some time to come."