Forbes estimated Messi’s yearly earnings at $126m with Juventus’ Cristiano Ronaldo second on $117m.
Neymar was in third place, with Paris St-Germain teammate Kylian Mbappe fourth.
Three Premier League players – Mohamed Salah, Paul Pogba and David de Gea – made the top 10, as did Real Madrid and Wales forward Gareth Bale.
Liverpool forward Salah was fifth, ahead of Manchester United midfielder Pogba in sixth, with United goalkeeper De Gea in 10th.
The top three were in the same order as in 2019, although Mbappe rose three places from seventh to fourth.
Argentine Messi, 33, tried to leave Barcelona this summer and submitted a transfer request in August, but decided to stay because no club would be able to afford his release clause.
Forbes list of highest-earning footballers
Cristiano Ronaldo (Juventus and Portugal) $117m
Neymar (Paris St-Germain and Brazil) $96m
Kylian Mbappe (Paris St-Germain and France) $42m
Mohamed Salah (Liverpool and Egypt) $37m
Paul Pogba (Manchester United and France) $34m
Antoine Griezmann (Barcelona and France) $33m
Robert Lewandowski (Bayern Munich and Poland) $28m
David de Gea (Manchester United and Spain) £27m.