Robert Downey Jr, 50, earned an estimated US$80 million between June 2014 and June 2015, spurred by the success of this year's superhero ensemble Avengers: Age of Ultron, which grossed more than US$1.3 billion worldwide.
Second-place honors went to veteran Chinese actor and martial arts star Jackie Chan, 61, who Forbes said had earned US$50 million in the past year from Hollywood and China co-productions such as Dragon Blade as well as merchandise.
Chan came in ahead of Hollywood stars Vin Diesel, who grabbed third place with US$47 million mainly due to his stake in the "Fast and Furious" franchise, as well as Bradley Cooper, Adam Sandler and Tom Cruise.
Sandler, 48, whose most recent big budget film Pixels performed poorly in the global box office, still earned US$41 million over the past year, in part due to his production deals with Sony studios and Netflix.
For the first time actors in non US movies have been included in the list.
Bollywood actors Amitabh Bachchan, Salman Khan and Akshay Kumar, all staples of Indian cinema, featured in the top 10, with 72-year-old Bachchan and 49-year-old Khan tying at No. 7 with $33.5 million each. Kumar, 47, came in at No. 9 with $32.5 million.
The 34 actors on the list, from seven countries, earned a combined US $941 million between June 1, 2014 and June 1, 2015.
Forbes collates its earnings lists using figures from sources such as Nielsen, Box Office Mojo and IMDB, and calculates earnings by deducting estimated taxes and management fees. It will publish a list on the world's highest-paid actresses at a later date.