Qatar Sports Investments said an agreement to buy almost 22% of shares in the 101-year-old club was declared to Portuguese financial authorities and the deal should be completed within months.
Braga are Europa League regulars, having reached the final in 2011 and played in the group stage in seven of the past eight seasons.
However, Champions League reforms taking effect in 2024 give a third direct entry to the group stage for the domestic league ranked No. 5 by UEFA, and Portugal is competing for that slot with France and the Netherlands.
Though UEFA rules bar clubs in shared ownership playing in the same competition, QSI's minority stake would likely avoid intervention if PSG were drawn against Braga.
"Braga is happy to be able to welcome Qatar Sports Investments as an investor," Braga president Antonio Salvador said. "We believe it is the right partnership to accelerate our growth and expansion, helping us to develop our great potential as a club. Qatar Sports Investments' extraordinary experience -- with its global experience and impressive results in both sports and business -- will bring us great value and help us to realise our ambitious plans. It is a great day for our club, for our fans and for our city; we look forward to the future successes of Braga."
QSI chairman Nasser Al-Khelaifi, who is also PSG president, described Braga as "an exemplary Portuguese institution with a proud history, enormous ambition and a reputation for excellence on and off the pitch."