The centre-back is the first defender to win the award since John Terry in 2005 and the fourth Dutchman after Dennis Bergkamp, Ruud van Nistelrooy and Robin van Persie.
Van Dijk, 27, signed for Liverpool from Southampton last January for £75 million, a world-record fee for a defender.
He has already shown he was worth the money, as his influence has transformed Liverpool from also-rans into genuine title challengers.
Liverpool could yet lose the title race this season despite accruing 91 points.
But manager Jurgen Klopp has formed a team that are capable of finally breaking Liverpool's 29-year title duck.
Establishing a world-class defence has been key to that.
This season Liverpool have conceded less than 0.6 goals per game in the Premier League.
Over the eight full Premier League seasons before the current campaign, that average was nearly 1.2.
Tightening up at the back has been crucial to Liverpool becoming title challengers, and Van Dijk's part in that transformation was acknowledged on Sunday.