He also finished ahead of fellow Barca frontman Neymar after a calendar year in which the Catalan outfit claimed five titles.
Argentina international Messi, who scored 48 goals for his club in 2015, said after being presented the award by 2007 Ballon d’Or winner Kaka: “It is very special for me to be back here on this stage, winning another Ballon d’Or after being there in the audience watching Cristiano win.
“It’s incredible this is my fifth. It’s much more than anything I’ve dreamed of as a kid.
“I want to thank everyone who voted for me.
“Lastly, I want to thank football in general for everything it has brought me.”
Messi secured 41.33% of the vote, with Portugal hitman Ronaldo getting 27.76% and third-placed Brazil striker Neymar 7.86%.
Republic of Ireland captain Robbie Keane voted for Ronaldo first with Messi second, while Martin O’Neill voted for Messi first, Eden Hazard second, and Ronaldo third.
Ireland’s media representative and Irish Examiner contributor Paul Kelly voted for Messi, then Luis Suarez, and Ronaldo.
Messi and Neymar helped Barca win the Primera Division, Copa del Rey and Champions League treble in 2015, plus the Uefa Super Cup and Fifa Club World Cup.
Ronaldo scored more goals than Messi over the calendar year, netting 54 for Madrid, but it was not enough for his side to win any silverware.
Monday’s ceremony also saw Barca boss Luis Enrique take the men’s world coach of the year award ahead of his predecessor, Pep Guardiola.
The category for world coach of the year for women’s football was won by USA coach Jill Ellis.
US midfielder Carli Lloyd claimed the women’s world player of the year gong.
John Terry, Wayne Rooney and Gareth Bale were the only British players to have made the 55-man shortlist.