The 30-year-old whose previous contract was expected to expire in 2023, follows Trent Alexander-Arnold, Fabinho and Alisson in signing new deals with the club this summer.
Van Dijk played just five league games last season, before suffering an anterior cruciate ligament injury in October.
The Dutch defender is expected to feature from the start of Liverpool's Premier League campaign having returned from injury during the pre-season.
The former Southampton man has established himself as a key prospect at Liverpool since arriving for a reported fee of £75 million in January 2018.
Van Dijk could have played in the Euro 2020 for Netherlands but opted not to play in order to focus on his rehabilitation.
The bulky defender has made 130 appearances in all competitions for Liverpool, as they begin their 2021-22 Premier League campaign at Norwich on Saturday.
Van Dijk said after signing the new deal;
“Amazing. It is something to be very proud of, that I am very proud of, that my wife and my kids are very proud of and obviously my agency.
“All the hard work we’ve put in so far continues and I am looking forward to what the future brings together with Liverpool. I’m delighted, very happy and proud.
"Since day one when I joined the club, I felt so much appreciation from the fans and from my teammates and the staff, that I could be a very important member of this football club,” Van Dijk continued.
“It has been going well; unfortunately last season for me personally has been a season to forget, to learn from and take with me, but I have enjoyed my time here and will keep enjoying it in the next couple of years altogether with all of you.”
Van Dijk individually was voted the PFA Players’ Player of the Year, UEFA Men’s Player of the Year and UEFA Defender of the Season for 2018-19, while he finished second in the 2019 Ballon d’Or and The Best FIFA Men’s Player in 2019.
