Juventus's Portugal forward Cristiano Ronaldo is second on $109m (£85.6m) with Paris St-Germain's Brazil forward Neymar in third on $105m (£82.5m).
The Barcelona star, who ranked second behind Floyd Mayweather Jr.in 2018, leads all athletes with $127 million in total earnings, including $35 million in endorsements, according to Forbes.
The top 100 athletes combined to earn more than $4 billion, which is a 4% jump from previous year when retired boxer Floyd Mayweather topped the list, earning $285 million.More news: Kyle Rudolph To Sign 4-Year, $36M Contract Extension With Vikings
This year's top earner from the sport of boxing, Saul "Canelo" Alvarez, earned just $2 million in endorsements, but his $92 million in salary/winnings matched those of Messi to place him fourth in the list.
Alvarez, who defeated Gennady Golovkin last September to become the unified middleweight champion, inked the richest deal in boxing history last October, signing a five-year 11-fight contract with streaming network DAZN worth $365m.
Manchester United star Paul Pogba is next footballer on the list but is the 44th highest earner overall.
LeBron James earned $89m in total with Stephen Curry having made $79.8m and Kevin Durant $65.4m.More news: Yuvraj Singh, World Cup 2011 hero, announces his retirement from worldwide cricket
Los Angeles Lakers star LeBron James was the highest earning National Basketball Association player, with $89m, while Golden State's Stephen Curry was ninth with $79.8m.
Former world number one Tiger Woods was 11th on the list with $69.3 million, which included an estimated $54 million in endorsements.
Meanwhile tennis superstar Serena Williams was the only woman to make the list, coming in at 63rd with earnings of $29.2m.More news: 3m Sudan strikes bring country to standstill