Teams will be allowed to make up to five substitutions in Uefa competitions until the end of the 2020-21 season.
The rule change was proposed by Fifa because of congested fixture schedules caused by the coronavirus pandemic.
In August, the Premier League said it would not adopt the rule change after clubs voted against it.
But Uefa president Aleksander Ceferin said it would be used in European competitions such as the Champions League and Europa League.
It will also be adopted in European national team matches, including the Nations League.
However, a decision has yet to be made on whether the rule will be adopted for next year's rearranged European Championships.
"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," he said.
World players' union Fifpro welcomed Uefa's decision.
"This is the right decision and a good first step to ease pressure on elite-level players," said the organisation's general secretary Jonas Baer-Hoffmann.
"We will continue to push for further innovative ways to reduce their mounting workload and protect their health and performance."
Manchester City manager Pep Guardiola, Liverpool boss Jurgen Klopp and Chelsea's Frank Lampard all wanted five substitutes to be kept in the Premier League.
Premier League managers were allowed to name 20 players and make five substitutions when the 2019-20 season resumed from its coronavirus shutdown, but it has now reverted to squads of 18 with three permitted changes.
Ceferin also said the executive committee had approved triple-header international breaks in March and September 2021.
'Health remains number one priority' - Ceferin on return of fans
Nothing has yet been decided about fans being allowed in stadiums for the start of the Champions League next month, Ceferin said.
Uefa has said about 15,500 tickets have been sold for tonight's Super Club clash between Bayern Munich and Sevilla in Budapest.
It is the first Uefa fixture to be played with fans since March and European football's governing body has urged those attending to observe all protocols to ensure the game passes without incident.
Uefa will then speak with the authorities in Hungary before deciding what to do about the Champions League and Europa League group stage games next month, plus the Nations League and Euro 2020 play-off games also due to be played in October.
"We have not decided anything about spectators in the future at European matches," said Ceferin.
"The easiest thing would be not to do anything and just stay and wait. But if you do nothing, nothing moves.
"Health remains the number one priority but we want to bring hope and do what we think is proper thing to do. We are not doing this because of revenue. Fans and players are an essential part of football."