GoKawiilGoogle has been fined €890m (£759m) by the EU for allegedly abusing its power by favouring its own apps and services over those from rivals.
It is the first major action against the tech giant under the EU's Digital Markets Act (DMA), a landmark law aimed at curbing the power of the world's biggest tech companies.
The Commission argued Google's practices limited consumer choice and gave its own services an unfair advantage over rivals.
But the firm criticised the decision, arguing the EU's requirements could damage services used by millions of European customers.
"To comply, we are having to strip away real-time Search features Europeans love - like instant pricing and direct availability for hotels, flights and restaurants - and dismantle safety protections on Google Play," said Google's president of global affairs Kent Walker.
"This isn't fair competition."
EU officials rejected that argument, saying the measures are necessary to prevent dominant platforms from disadvantaging rivals.
The total fine handed down to Google comprises of two separate breaches of the DMA.
The European Commission imposed a €460m penalty after finding Google favoured its own services for helping people book flights and hotels over competitors in search results.
And it gave the firm a further €430m fine due to its Play Store rules, with regulators saying it didn't allow people to be shown cheaper offers available outside Google's own marketplace.