The Notorious enjoyed a lavish bash to mark the occassion
Among those who joined the MMA star at the Spanish party spot was his fiance Dee Devlin, mother Margaret, sister Erin, niece Taylor and his many friends and family members.
A professional photographer was on hand to capture memories for the birthday boy.
The Crumlin native posed with party-goers who were treated to two signature cocktails, ‘Tríocha A Ceathair’ and ‘The Notorious’ made with his very own Proper Twelve whiskey.
Models strutted their stuff as they carried bottles of the liquor around the venue.
A massive birthday cake, embellished with his name in icing, as well as a UFC belt, depicted the fighter in the octagon cheering.
As sparklers were lit on the centrepiece, the Dubliner stripped off his shirt as the crowd sang Happy Birthday.
“What a birthday party, thank you team ❤️,” he said sharing a carousel of snaps on Instagram.
“Ain’t No party like a Mac Daddy party #ibiza,” he captioned another series of pictures.
The Notorious, who turned 34 on Thursday, had his luxury yachts brought out to Ibiza for ahead of the birthday celebrations.
His €3.5 million Lamborghini Tecnomar 63 – dubbed the “Supercar of the Sea” - joined him in the Balearic Islands for the party.
McGregor is believed to have packed out his yacht with up to €500,000 worth of customisation - mostly featuring his Proper Twelve branding, named after the whiskey he promotes.
He also owns a triple-deck super yacht with an inflatable water slide, a climbing wall, and a “sea pool”, which greeted him in Ibiza during the week.