Norway forward Haaland, 23, scored 52 goals in all competitions in his debut season with Pep Guardiola's side.
City won the Premier League, FA Cup and Champions League Treble last season.
"It's an honour to win this prestigious award," said Haaland. "To be recognised by your competitors is a great feeling and I would like to thank everyone who voted for me.
"It was an unforgettable season for the team and for me personally. Winning the Treble was something I never imagined, so to achieve that with such a special group of players was an amazing feeling.
"We created some incredible memories last season, but now we want to do the same again this year. We have started the season well and we need to keep going."
Haaland joined City from Borussia Dortmund in a deal worth £51.2m in June 2022.
He was also nominated for the young player prize, which was awarded to England winger Saka after he scored 14 goals and contributed 11 assists in his finest season for the Gunners.
The 21-year-old beat fellow nominees Moises Caicedo, who recently joined Chelsea from Brighton, Aston Villa midfielder Jacob Ramsey, Arsenal forward Gabriel Martinelli and Brighton striker Evan Ferguson.
Meanwhile, both winners of the individual prizes were also included in the PFA Team of the Year.
Aston Villa striker Rachel Daly won the PFA women's Player of the Year award, while Chelsea's Lauren James was named Young Player of the Year.
PFA Team of the Year: Aaron Ramsdale (Arsenal), William Saliba (Arsenal), Ruben Dias (Man City), John Stones (Man City), Kieran Trippier (Newcastle), Rodri (Man City), Martin Odegaard (Arsenal), Kevin de Bruyne (Man City), Bukayo Saka (Arsenal), Harry Kane (Tottenham), Erling Haaland (Arsenal).
Burnley dominate PFA Championship Team of the Year
Champions Burnley had four players included in the PFA Championship Team of the Year, while forward Chuba Akpom, at Middlesbrough last season, was named the second-tier's Player of the Year.
Akpom, who left Boro for Ajax in a deal worth up to 14.3m euros (£12.2m) earlier this month, scored 29 goals in all competitions and finished the season as the league's top scorer.
Conor Chaplin was rewarded for his 29 goals in all competitions as he was named League One Player of the Year as Ipswich won promotion to the Championship.
Bradford City's Andy Cook took the League Two Player of the Year prize after his 31 goals, including 28 in the league, saw the Bantams reach the play-offs.
PFA Championship Team of the Year: Arijanet Muric (Burnley), Ian Maatsen (Burnley), Connor Roberts (Burnley), Anel Ahmedhodzic (Sheffield United), Tom Lockyer (Luton), Nathan Tella (Burnley), Josh Brownhill (Burnley), Iliman Ndiaye (Sheffield United), Chuba Akpom (Middlesbrough), Viktor Gyokeres (Coventry), Carlton Morris (Luton).
PFA League One Team of the Year: James Trafford (Bolton), Mads Andersen (Barnsley), Ricardo Santos (Bolton), Bali Mumba (Plymouth), Leif Davis (Ipswich), Luca Connell (Barnsley), Sam Morsy (Ipswich), Barry Bannan (Sheffield Wednesday), Conor Chaplin (Ipswich), Jonson Clarke-Harris (Peterborough), David McGoldrick (Derby).
PFA League Two Team of the Year: Lawrence Vigouroux (Leyton Orient), Ibou Touray (Salford), Junior Tchamadeu (Colchester), Omar Beckles (Leyton Orient), Carl Piergianni (Stevenage), Elliot Watt (Salford), Owen Moxon (Carlisle), Idris el Mizouni (Leyton Orient), Sam Hoskins (Northampton), Andy Cook (Bradford), Paul Smyth (Leyton Orient).