Denis O'Brien, Irish businessman, founded BT Ireland
Denis O'Brien (born 19 April 1958) is an Irish billionaire businessman, and the founder and owner of Digicel. He was listed among the World's Top 200 Billionaires in 2015 and is also Ireland's richest native-born citizen. His business interests have also extended to aircraft leasing (Aergo Capital), utilities support (Actavo), petroleum (Topaz Energy), football (a minority shareholder of Celtic F.C.), and healthcare (Beacon Hospital). As former chairman of the Esat Digifone consortium, O'Brien was questioned by the Moriarty Tribunal, which investigated the awarding of a mobile phone licence to Esat, among other things.

In 2021, O'Brien sold his stake in Communicorp and the Pacific operations of Digicel. O'Brien engages in various philanthropic activities, including being on the board of Concern Worldwide, founding the Iris O'Brien Foundation and establishing a fellowship at Boston College. In 2019, O'Brien earned the Award for Outstanding Achievement from the Irish-US Council.