RANKED: The 16 busiest airports in the world
According to the ACI, this represents an increase in traffic of over 5.5% over 2014. The trade group attributes Atlanta's success to its strategic location, where it is within a two-hour flight of 80% of the US population.
In addition, the ACI credits the growth of ATL's largest tenant - Delta Air Lines - for the airport's continued expansion in the traffic. Globally, the number people traveling by air grew at a rate of 6.1% in 2015.
"It's impressive to witness the dynamic character of the aviation industry and its evolution over time," ACI World general director Angela Gittens said in a statement.
"Even in the most mature markets such as the United States and parts of Western Europe, several of the major hubs experienced year-over-year growth rates in passenger traffic that were well above the historical growth levels for these regions.
The trade group compiled its list using passenger traffic data from 1144 airports located around the world.
Here are the 16 busiest airports in the world based on total passenger traffic.