EU ambassadors agreed to ban Belarus airlines from flying over the bloc's territory or landing at its airports.
It is the latest step taken by Brussels in response to the arrest of an opposition journalist whose plane last month was forced into an emergency landing by Belarus's military.
The flight ban will take effect at midnight, diplomats involved in the talks told Reuters.
Enforcement of the ban will fall to EU governments, many of whom are also members of Nato and can scramble fighter jets to protect their airspace.
Belarus's national carrier, Belavia, usually operates flights linking the country with airports including those in Paris, Berlin, Rome and Vienna.
The EU is also recommending that its airlines avoid flying over Belarus, but this does not amount to a legally binding ban.
Air traffic control agency Eurocontrol said that about 400 civilian planes usually fly over Belarus every day.
Lufthansa, Air France and Finnair are among the airlines who have announced that they will stop flying over the country.
The EU’s move is part of broader sanctions against the regime of Belarusian President Alexander Lukashenko.
Britain, the US and EU all imposed sanctions on Belarus officials last year after an election that the opposition said was rigged.
On May 23, journalist Roman Protasevich was arrested after the Belarusian military scrambled a warplane to force a Ryanair plane to land in Minsk.
The flight from Athens to Vilnius was diverted when Belarus claimed there was a bomb threat, which world powers suspect was a ruse to arrest the journalist.
Sviatlana Tsikhanouskaya, the main opposition figure in Belarus, on Friday called for the EU, the UK and the US to jointly put more pressure on Mr Lukashenko.
“Pressure is more powerful when these countries are acting jointly,” she said. “They have to act jointly so their voice will be more loud.”
The opposition leader said she expected that Belarus would be discussed at next week’s G7 summit in Cornwall.
Belarusian state media broadcast an interview with Mr Protasevich on Thursday in which he admitted calling for protests and praised Mr Lukashenko.
Ms Tsikhanouskaya on Friday dismissed the interview, saying Mr Protasevich was a political prisoner.
"All such videos are shot under pressure. We don't have to pay attention even to these words because they are done after torture," she said.