Teams will be able to make five substitutions in UEFA competitions for the rest of the season, the organisation's president Aleksander Ceferin has said.
The law amendment was proposed by world governing body FIFA to assist clubs in managing player workload in a congested calendar created by the coronavirus pandemic.
While it has not been adopted for the 2020-21 season by the Premier League, which has reverted to three substitutes, Ceferin said at a press conference that UEFA's executive committee had approved it for club competitions such as the Champions League and the Europa League and in national team matches.
Ceferin said: "After representations from clubs and national associations the executive committee approved the use of five substitutions in club and international matches for the rest of the season."
The executive committee also approved triple-header international breaks in March and September next year, he said.
The international windows in October and November 2020 had already been extended by one day by FIFA, to allow for three matches to be played by each country instead of two.
Ceferin also announced the 2021 UEFA Congress will take place in Switzerland in March next year, rather than the Belarusian capital Minsk.
The city in the former Soviet republic has witnessed popular uprisings against president Alexander Lukashenko, who was controversially re-elected in August.
World players' union FIFPRO welcomed the decision on allowing five substitutes.
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The organisation's general secretary Jonas Baer-Hoffmann said: "This is the right decision and a good first step to ease pressure on elite-level players.
"We will continue to push for further innovative ways to reduce their mounting workload and protect their health and performance."
'With five substitutions we protect the players'
The Premier League reverted to allowing three substitutions from a bench of seven this season after changing the rules to permit five from nine during Project Restart last term.
Some clubs, thought to include the so-called 'big six', were in favour of retaining five substitutions but were outvoted, with others feeling it gave rivals with bigger squads an additional advantage.
Speaking ahead of Manchester City's opening Premier League game against Wolves, City boss Pep Guardiola said he believed the decision was a mistake.
"I don't understand why in this incredible period, when everyone is concerned about Covid-19, and everyone is not allowed to go to restaurants, or should not go to the restaurants, or should observe social distances, and is not allowed to do what you want to do," Guardiola said.
"And in this incredible schedule we have after the pandemic, and we finished the season late, and started quickly, how we cannot protect the players with five substitutions, and instead we stick to three.
"The guys who are going to play below the five or six teams that people suggest are the stronger have the same problem. They have games every three days.
"We have to protect the players and with five substitutions we protect the players, but I don't decide these kind of situations."