Canada was McDonald's first international market after the United States.
McDonald's entered Canada in 1967 by opening a restaurant in Richmond, British Columbia. The move was a major branding milestone because it showed that the company's recognizable restaurant format could cross a national border while preserving its core visual identity.
The Canadian expansion came before McDonald's entered many of the markets most associated with its global presence. The company opened in Costa Rica in 1970, Australia in 1971, and Japan in 1971, so those countries were international pioneers but not the first.
This fact is distinct from the question of McDonald's first restaurant outside the United States: both point to Canada, but one emphasizes the market while the other emphasizes the opening itself.