Ireland should recover as much as €13bn (£11bn) in back taxes from Apple, the European Commission has ruled.
The ruling follows a three year investigation into Apple’s tax affairs in Europe, which the EU had previously identified as illegal.
Under EU law, countries are not allowed to give unique tax benefits to selected companies as such deals would be considered state aid.
EU authorities have previously said Irish government rulings in 1991 and 2007 have allowed Apple, which legally funnels the profits from its international sales through Ireland, to unfairly minimise its profits.
On Tuesday, EU competition commissioner Margrethe Vestager estimated the value of the back taxes Apple should pay to Ireland at €13bn, but it is up to Irish authorities to determine the exact amount.
Apple is the latest US multinational to face investigation by EU authorities over their tax structure, with Starbucks ordered to pay as much as €30m (£25.6m) to the Netherlands in 2015.
Apple will likely face a considerably larger bill, but with cash reserves of over $200bn (£153bn) on hand, the US technology giant will not struggle to pay up.
Apple and the Irish government are expected to appeal the ruling.