Treble (association football)

A treble in association football is when a club team wins three trophies in a single season. A "continental treble" is when a clubs wins the national league competition, the main national cup competition and the main continental trophy. A "domestic treble" is when a clubs wins three national competitions. Usually this means the league title, the main cup competition and one secondary competition.
Continental trebles.
This list has clubs who have won their country's highest level league and the primary cup competition (the double), as well as the main continental tournament, all in the same season. Celtic was the first club to do this in 1967. They won the Scottish Football League, Scottish Cup, and European Cup. They also won the Scottish League Cup that year. This makes them the only team in history to win the domestic treble and the European Cup in the same season (although most European nations do not have a League Cup).
In men's football, seven European clubs have achieved the treble since 1967. FC Barcelona and Fc Bayern are the only clubs to win this treble twice. Cruz Azul is the only Mexican team to win a continental treble. It has done this twice, in 1969 and 1997.
No South American team has achieved the treble. This is because many countries there do not (or did not) have a major knockout cup. The Copa do Brasil only began in 1989, and the Copa Argentina began in 2011. Uruguay still does not have a knockout cup.