In 2016, the European Commission ordered Apple to pay 13 billion euros ($A22 billion) in back taxes, arguing that the US company had underpaid taxes due in the bloc following a suspected sweetheart deal with EU member Ireland.
Apple filed a successful complaint with the EU's general court, arguing the commission had failed to prove that the contested tax deal constituted prohibited state aid.
The iPhone manufacturer had also told the EU court that the earnings of its two Irish subsidiaries at issue had been primarily taxable in the United States, and that the company was being asked to pay twice.
The commission appealed against the general court's annulment of the payment order in 2020, and it is now up to the EU's highest court, the European Court of Justice (ECJ), to make a final ruling in the case.
The European Court of Justice in Luxembourg will deliver its ruling on Tuesday. (AP PHOTO)
In a separate appeals case, the ECJ is to rule on a 2.4 billion euro fine for Google, also imposed by the European Commission, over an alleged breach of EU competition rules.
The commission argues the search engine operator favoured its own price comparison service Google Shopping over its competitors and therefore abused its market power.
Google has already unsuccessfully logged a complaint with the EU's general court and is appealing to the bloc's highest jurisdiction.
