The fine is the largest penalty ever imposed by the European Commission and comes as the web giant is already fighting a previous record fine of €2.4bn (£2.2bn) for using Search to give its own online shopping service an illegal advantage.
Google Search is pre-installed as the default web search service on most Android devices sold in Europe, closing off ways for rival search engines to access the market according to the EU ruling.
This happened because Google gave companies financial incentives to pre-install its apps which also prohibited them from making alternative devices using competing operating systems.
The EU’s competition commissioner Margrethe Vestager said Google was in breach of competition law barring companies from exploiting their market dominance.
“Google must now bring the conduct effectively to an end within 90 days or face penalty payments of up to 5% of the average daily worldwide turnover of Alphabet, Google’s parent company,” the EU said.
Google plans to appeal against the decision.
“Android has created more choice for everyone, not less. A vibrant ecosystem, rapid innovation, and lower prices are classic hallmarks of robust competition,” said a spokesperson for the company.
The EU’s competition office, which has earned a reputation under Ms Vestager for tackling American technology giants, also has an ongoing investigation into Google’s advertising business AdSense.
Android is the most widely used mobile OS in the world, installed on roughly 76% of all smartphones, including those manufactured by Samsung, Sony and Huawei.
Google Search is also the most widely used search engine in the world, performing roughly 95% of all searches despite the efforts of competing services such as Bing and DuckDuckGo.
Calls to extend the ruling from the EU to the US competition regulators have followed the announcement of the fine.