Its huge success has been linked to performances from big name acts including One Direction, Robbie Williams and Florence and the Machine.
Co Down band Snow Patrol enjoyed two sold out gigs, while gigs from Dublin band the Coronas and a two-night extravaganza from R&B stars Kanye West and Jay-Z were big earners last year.
As a result the venue jumped one place in this year's figures, compiled by US-based industry journal Pollstar. The O2 arena in London was the world's best attended venue last year. The ranking was achieved despite a 17pc drop in sales as the number of visitors fell by 8pc to 620,555.
One Direction grossed €275,216 for one gig last January and the boyband stars, who include Mullingar native Niall Horan, have sold out four nights at the concert venue for a run of gigs this March.
Other poplar music stars included Take That star Robbie Williams who took in €462,090 in September, and Florence and the Machine who grossed €1m from her two gigs.
This weekend will see Ed Sheeran bring another sell-out crowd to the north Dublin venue.
Snow Patrol grossed €1m from their gigs last January, while the Coronas' sold 94pc of tickets for their December gig, grossing €457,602.
The most lucrative single gig staged by an Irish artist was last January when Van Morrison grossed €684,518 from his sold-out single night.
The O2 staged 87 box office gigs last year compared to 82 in 2011.
The gross receipts for all concerts are shared between the promoter, artist and venue operator and do not include revenues from merchandise or food and alcohol sales.
Despite attracting an array of pop acts last year, comedian Michael McIntrye drew in the biggest revenue for his stint in the O2. He entertained 35,438 fans over four sold-out nights last November, grossing €1.57m.
Fellow comic John Bishop was another top grossing acts, raking in €1.35m for his four-night stint.
The top earner at the O2 last year was Cirque du Soleil, with sales of €1.7m for seven shows.
Acts that failed to pull in the crowds included Cheryl Cole whose October gig was only 52pc full, while Guns N' Roses had a 47pc crowd capacity in May.
Most recent records show that the venue recorded pre-tax profits of €7.4m in 2011.
The main promoters behind the concerts last year were MCD Productions and Aiken Promotions.