Restaurant Brands International is a Canadian multinational fast food company. Formed in 2014 by the $12.5 billion merger between American fast food restaurant chain Burger King and the Canadian coffee shop and restaurant chain Tim Hortons, and expanded by the 2017 purchase of Dunwoody, Georgia, U.S. - based and themed Popeyes Louisiana Kitchen, the company is the third-largest operator of fast food restaurants in the world. The company is based alongside Tim Hortons in Oakville, Ontario, but both chains retain their existing operations and headquarters in Oakville and Miami respectively. The merger focused primarily on expanding the international reach of the Tim Hortons brand, and providing financial efficiencies for both companies.

The company is majority-owned by the Brazilian investment company 3G Capital—the previous majority owner of Burger King—holding a 51% stake. The remainder of the company is publicly traded on the New York and Toronto Stock Exchanges, and owned by the prior shareholders of Burger King and Tim Hortons. The deal was approved by Tim Hortons' shareholders on December 9, 2014, and the company began trading on December 15, 2014.

On August 24, 2014, U.S. fast-food chain Burger King announced that it was in negotiations to merge with the Canadian coffee shop and restaurant chain Tim Hortons; the proposed merger would involve a tax inversion into Canada, with a new holding company majority-owned by Burger King's current majority-owner 3G Capital, and the remaining shares in the company held by current Burger King and Tim Hortons shareholders. A Tim Hortons representative stated that the proposed merger would allow Tim Hortons to leverage Burger King's resources for international growth; the two chains would retain separate operations post-merger. News of the proposal caused Tim Hortons' shares to increase in value by 28 percent.

On August 25, 2014, Burger King officially confirmed its intent to acquire Tim Hortons Inc. in a deal totaling CDN$12.5 billion (US$11.4 billion). 3G Capital purchased the company at $65.50 per-share, and existing shareholders received $65.50 in cash and 0.8025 shares in the new holding company: per-share—all-cash ($88.50) and all-shares (3.0879) options would also be available. Due to its iconic status in Canadian culture, CEO Marc Caira reassured the integrity of Tim Hortons following the purchase, stating that the acquisition would "enable us to move more quickly and efficiently to bring Tim Hortons' iconic Canadian brand to a new global customer base".

Although tax inversions, a process in which a company decreases the amount of taxes it pays by moving its headquarters to a country with lower rates, but maintains the majority of their operations in their previous location, have been a recent financial trend, it did not have as much of an impact on Burger King's reincorporation in Canada. The corporate tax rate in the United States is 39.1%, while Canada's corporate tax rate is only 26%: however, Burger King had already used various sheltering techniques to reduce its tax rate to 27.5%. As a high-profile instance of tax inversion, news of the merger was criticized by U.S. politicians, who felt that the move would result in a loss of tax revenue to foreign interests, and could result in further government pressure against inversions (which had, until the Burger King merger, been primarily invoked by pharmaceutical firms). 3G Capital co-founder Alex Behring denied that the merger was tax-related, stating that it was "fundamentally about growth and creating value through accelerated expansion".

The deal was approved by the Canadian Competition Bureau on October 28, 2014, ruling that the deal was "unlikely to result in a substantial lessening or prevention of competition". The deal was approved by Minister of Industry James Moore on December 4, 2014: the two companies agreed to conditions, requiring that the Burger King and Tim Hortons chains retain separate operations, not combine locations in Canada and the United States, maintain "significant employment levels" at the Oakville headquarters, and ensure that Canadians make up at least 30% of Tim Hortons' board of directors. Tim Hortons shareholders approved the merger on December 9, 2014: the same day, it was announced that the new holding company would be known as Restaurant Brands International, and trade under the ticker symbol QSR. Vice-chairman Marc Caira felt that the merger was the "next chapter" for Tim Hortons, envisioning a "bolder, more assertive, and dynamic Tim Hortons in the future" alongside its prospects for international expansion.

On February 21, 2017, Restaurant Brands International announced its intent to acquire Popeyes Louisiana Kitchen for US$1.8 billion at US$79 per share. On March 27, the deal closed with RBI purchasing Popeyes at $79 per share via Orange, Inc, an indirect subsidiary of RBI.

3G Capital (which held a 71% majority stake in Burger King) holds a 51% majority stake in Restaurant Brands International. Berkshire Hathaway, who partially funded the merger, holds a 4.8% stake. Burger King CEO Daniel Schwartz serves as CEO of the company, with previous Tim Hortons CEO Marc Caira being vice-chairman and director. Elías Díaz Sesé, formerly of Burger King's Asia-Pacific operations, was named the new president of Tim Hortons, while Jose Cil, formerly of Burger King's EMEA operations, was named the new president of Burger King.