The Tottenham Hotspur and Wales midfielder rounded off a remarkable season by becoming the first player since Cristiano Ronaldo to do the double at the prestigious ceremony.
Bale beat off competition from last year's winner Robin van Persie, who was third in the vote behind Luis Suarez and Bale, while Michael Carrick, Eden Hazard and Juan Mata were the other nominees.
The 23-year-old has scored 19 goals in 29 games for Spurs and also had four assists and created 68 chances in a stellar season.
Bale said: "It's a massive honour. To be voted by your peers is one of the biggest things in the game. It's great to win it and I am delighted.
"When you look at the list, there are some massive names on it but I couldn't have done it without the team. They have been fantastic this year and so has the manager. "
The Welshman also took home the Young Player of the Year award, making him only the third player in history after Ronaldo in 2007, while at Manchester United, and Aston Villa's Andy Gray, 30 years earlier, to receive both prizes in the same season.
Bale also won the senior award two seasons ago when he shot to fame with a series of scintillating displays domestically and in the UEFA Champions League.
The official vote in the Young Player category saw Villa's Christian Benteke finish in second, Eden Hazard in third with Romelu Lukaku, Danny Welbeck and Jack Wilshere the other nominations.
PFA chief Gordon Taylor thinks Bale is a good role model to the youth of today.
He said: "Everyone knows Suarez is a great footballer, I just wish at times he could fall in to line because footballers are role models and Gareth and Robin van Persie are really good examples for the younger generation."
Arsenal Ladies midfielder Kim Little, meanwhile, won the inaugural PFA's Women's Player of the Year award and the Scot said: "It is a great night for me. For various years I have watched this event on television so to come here and win the first award is fantastic."
Bale had previously spent most of his career deployed on the left flank for Tottenham and his first club Southampton but this term he has played more centrally, which he thinks is the reason why he has scored so many times.
"I have been shooting a lot more, and I have been coming inside a lot more, too," he added.
"There are a few goals which I enjoyed. The one against Norwich was one of my favourites, and the West Ham one.
"Those two are my favourites from this season. I have a few less assists this year but I am in more scoring positions these days and that has obviously helped my scoring tally as we have seen this season."