Alphabet unit Google on Tuesday challenged a record 4.34-billion euro ($5 billion) fine imposed by European Union antitrust regulators three months ago for using the Android mobile operating system to thwart rivals.
"We have now filed our appeal of the EC's Android decision at the General Court of the EU," Google said.
The European Commission in its July decision said Google had abused its market dominance since 2011. Android, used by device makers for free, is found on about 80 percent of the world's smartphones.
EU competition enforcers had said Google's illegal practices included forcing manufacturers to pre-install Google Search and its Chrome browser together with its Google Play app store on their Android devices.
The EU antitrust authorities said the company also paid manufacturers to pre-install only Google Search and blocked them from using rival Android systems.