Dublin Airport Authority (DAA) said business from Northern Ireland grew about twice as fast as average passenger numbers at the airport.
Passenger numbers rose by almost 6% to 20.2m in 2013.
Dublin Airport spokesman Paul O'Kane said there was a "strong growth" in passengers from Northern Ireland.
"Dublin Airport plays a major role in bringing visitors from Europe, North America, and further afield to Northern Ireland," Mr O'Kane said.
"Dublin Airport is particularly strong on long-haul routes to North America, and the Middle East and on direct short-haul services to a wide range of European locations, all of which provide large numbers of inbound visitors to Northern Ireland."
Heathrow and Gatwick airports are both in the top three destinations for Northern Ireland passengers.
All the London airports combined make up 17% of overall trips by Northern Ireland residents using Dublin Airport in 2013.
Short-haul services to Britain and continental Europe account for six of the top 10 routes for Northern Ireland residents, with long-haul services to North America and the Middle East providing the remaining four locations in the top 10.
The UK is the most popular destination for Northern Ireland residents using Dublin Airport, as it accounted for 20% of overall traffic - equivalent to one in five flights - last year.
The United States was the second most popular destination for Northern Ireland residents flying from Dublin Airport last year, while Italy, Germany and France also featured in the top five.
The number of Northern Ireland residents using Dublin Airport increased by 11% to more than 570,000 last year, figures have shown.