Juan Santamaría International Airport (Spanish: Aeropuerto Internacional Juan Santamaría) (IATA: SJO, ICAO: MROC) is the primary airport serving San José, the capital of Costa Rica. The airport is located in Alajuela Province, 20 kilometres (12 mi; 11 nmi) northwest of downtown San José. It is named after Costa Rica's national hero, Juan Santamaría, a drummer boy who died in 1856 defending his country against forces led by William Walker, an American filibuster. It is the biggest and busiest airport in Costa Rica and second in Central America with more than 5 million passengers per year before COVID

The airport is a hub for Avianca Costa Rica, Costa Rica Green Airways, Sansa Airlines, and Volaris Costa Rica and a focus city for Avianca El Salvador and Copa Airlines. It was the country's only international gateway for many years, before the opening of the international airport in Liberia, Guanacaste. Both airports have direct flights to North and Central America and Europe, but Juan Santamaría International Airport also serves cities in South America and the Caribbean.

Juan Santamaría International Airport was once the busiest airport in Central America, but is currently second after Tocumen International Airport in Panama. In 2022, Juan Santamaría International Airport received 5 million passengers (international and domestic).