The 1939–40 Athletic-Aviation Club season was one of the most successful seasons in the history of Atlético Madrid.

Atlético, who merged with Club Aviación Nacional at the start of the season, on 4 October 1939, won three titles within the next 12 months, the 1939 Campeonato Mancomunado Centro in November,[1][2] the 1939–40 La Liga in April,[3] and the 1940 Spanish Super Cup in September, although the latter was won in the following season.

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Players may hold more than one non-FIFA nationality.

Source: [1] In the following season, in 1940–41, Atlético Aviación won two more titles, the 1940 Spanish Super Cup in September, in which they beat RCD Espanyol 10–4 on aggregate,[4] and the Copa Presidente Federación Castellana, in which they beat Real Madrid 3–1 on aggregate.