The Serie A (Italian pronunciation: [ˈsɛːrje ˈa]), also called Serie A TIM for national sponsorship with TIM, is a professional league competition for football clubs located at the top of the Italian football league system and the winner is awarded the Scudetto and the Coppa Campioni d'Italia. It has been operating as a round-robin tournament for over ninety years since the 1929–30 season. It had been organized by the Direttorio Divisioni Superiori until 1943 and the Lega Calcio until 2010, when the Lega Serie A was created for the 2010–11 season. Serie A is regarded as one of the best football leagues in the world and it is often depicted as the most tactical and defensively sound national league. Serie A was the world's strongest national league in 2020 according to IFFHS, and is ranked fourth among European leagues according to UEFA's league coefficient – behind the Bundesliga, La Liga and the Premier League, and ahead of Ligue 1 – which is based on the performance of Italian clubs in the Champions League and the Europa League during the previous five years. Serie A led the UEFA ranking from 1986 to 1988 and from 1990 to 1999.

In its current format, the Italian Football Championship was revised from having regional and interregional rounds, to a single-tier league from the 1929–30 season onwards. The championship titles won before 1929 are officially recognised by FIGC with the same weighting as titles that were subsequently awarded. Similarly, the 1945–46 season, when the round-robin was suspended and the league was played over two geographical groups due to the ravages of World War II, is not statistically considered, even if its title is fully official.