The former Barcelona captain saw off competition from Bayern Munich striker Robert Lewandowski and Chelsea midfielder Jorginho to win football’s most prestigious individual honour again.
Messi has now pulled two clear of greatest rival Cristiano Ronaldo, who has won the award for five times.
The 34-year-old, who joined PSG on a free transfer in the summer, won the Copa del Rey with Barcelona last season and was top scorer in the Spanish top flight, while he finally ended his international trophy hoodoo by captaining Argentina to Copa America triumph.
"It's incredible to be here again," Messi said at the ceremony, held at Paris's Theatre du Chatelet.
“Two years ago, I said that it was my last years, and that I didn't know what was going to happen, and now I am here again.
“After that they began to ask me when I was going to retire and today I am in Paris. I am very happy and very excited, eager to continue fighting for new challenges.
“I don't know how much I have left, but I hope it's a lot, because I love this. Other times I won this award and I always had the feeling that something was missing.
“I felt gutted about something, and this year I was able to achieve the dream that I wanted so much after having fought and having gone through many falls.
“This award is largely because of what we (Argentina) did in the Copa America.”
Messi also had fond words for Lewandowski, who was widely expected to win the award in 2020, but was cancelled because of the coronavirus pandemic.
"[Lewandowski], you deserve your Ballon d'Or," Messi said upon receiving the award. "Last year, everyone was in agreement to say that you were the big winner.
"Hopefully [France Football] give you the Ballon d’Or 2020."