Ronaldo and Messi have monopolised the accolade for the past seven years, but Rivaldo feels his compatriot is worthy of claiming the sport's top individual playing prize.
Global footballing body FIFA will announce the recipient on January 11.
"I would like to say that it has been good to see Neymar playing for Barcelona, and especially with the number 11 shirt, which I know very well," Rivaldo wrote via Instagram.
"I do not know who will be 2015 best player in the world, but in my humble opinion, respecting Cristiano Ronaldo and Messi and others, Neymar deserves to be the best in the world."
The 23-year-old Neymar, who captains the Samba Boys, has been in fine form for Barcelona this season, netting 11 goals in 10 League matches for the La Liga leaders.