Dias was also named England's Footballer of the Year in the annual vote of the Football Writers' Association last month following a superb debut campaign after his move from Benfica last year
Manchester City's Ruben Dias and Phil Foden were named the Premier League's best player and best young player of the season Saturday, while City boss Pep Guardiola was named Manager of the Season for a third time.
Defender Dias becomes the second Portuguese to receive the honor after former Manchester United forward Cristiano Ronaldo.
Center back Dias was also named England's Footballer of the Year in the annual vote of the Football Writers' Association last month following a superb debut campaign after his move from Benfica last year.
Dias played a key role in delivering City's third Premier League title in four years as well as the League Cup, and helped his side the Champions League final.
The 24-year old was also named in the Professional Footballers' Association Team of the Year.
Dias is the fourth defender to be voted Player of the Season by the public, the captains of the 20 Premier League clubs and a panel of experts after United's Nemanja Vidic, former City captain Vincent Kompany and Liverpool's Virgil van Dijk.
Other nominees for the award this season included Kevin de Bruyne, Bruno Fernandes, Jack Grealish, Harry Kane, Mason Mount, Mohamed Salah and Tomas Soucek.
Foden made 28 appearances for City, finishing with nine goals and five assists to earn a spot in England's European Championship squad.
The 21-year old midfielder has also been nominated for the PFA men's Player of the Year alongside Dias, as well as for the Young Player of the Year award, with the winners set to be announced Sunday.
Guardiola won the manager's award in 2017-18 and again in 2018-19 when he led City to consecutive league titles.
Under the Spaniard, City conceded the fewest goals (32) this season and kept clean sheets in half of their games (19) to finish 12 points clear of second-placed United.
Guardiola won the award ahead of fellow nominees Marcelo Bielsa (Leeds United), David Moyes (West Ham United), Brendan Rodgers (Leicester City) and Ole Gunnar Solskjaer (United).