The 31-year-old England international joined Liverpool from Sunderland in the summer of 2011 and has made 394 appearances for the Reds.
Henderson’s previous contract would have expired in the summer of 2023.
Henderson joins the likes of Alisson Becker, Trent Alexander-Arnold, Virgil Van Dijk, Andy Robertson and Fabinho in signing new contracts at Anfield this summer.
Henderson was appointed Liverpool captain after Steven Gerrard left the club in the summer of 2015 and has led them in winning the Premier League title, UEFA Champions League, UEFA Super Cup and FIFA Club World Cup. He also won the League Cup in 2012.
Henderson told the club's official website: "I'm obviously very honoured and proud to continue the journey I've already been on here.
"It's amazing to finally get it done and just concentrate on looking forward and what the future may hold.
"I'm in a different place of course, as a player and as a person, from when I first walked in. I've learned and grown a lot over my time here, and I've got to thank a lot of people for that.
"I've loved every minute of it, even when I look back at the tough times, I was still enjoying being a part of this football club. The longer I can do that, the better for me really. I want to be here as long as possible, I've always said that.
"To continue this journey is incredible for me and my family, and I hope the fans and the club feel the same way."
