Goal reports the deal will keep Henderson contracted at Anfield until 2023, taking him past a decade of years service at the club.
Henderson told Liverpool's official website: "I'm very happy to have signed a new contract for a long period of time. I'm absolutely delighted.
"It doesn't seem like too long ago when I signed my first one – it feels like yesterday, really – but a lot has happened since then.
"I feel it's been a progressive journey for me throughout my time here and one I've enjoyed so much.
"There is no other place in the world I would rather play football. I want to be here for as long as I can be.
"I'm so privileged to have been a part of this club for so long, and hopefully even longer now."