Serie A (Italian pronunciation: [ˈsɛːrje ˈa]), also called Serie A TIM for sponsorship reasons, 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 third among European leagues according to UEFA’s league coefficient, behind La Liga and the Premier League and ahead of the Bundesliga and 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 recognized 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 WWII, is not statistically considered, even if its title is fully official.

The league hosts three of the world’s most famous clubs as Juventus, AC Milan, and Inter Milan, all founding members of the G-14, a group which represented the largest and most prestigious European football clubs from 2000 to 2008, with the first two also being founding members of its successive organization, European Club Association (ECA). More players have won the Ballon d’Or award while playing at a Serie A club than any league in the world other than Spain’s La Liga, although La Liga has the highest total number of Ballon d’Or winners. Juventus, Italy’s most successful club of the 20th century and the most successful Italian team, is tied for sixth in Europe and twelfth in the world with the most official international titles with eleven. Milan is joint third club overall for official international titles won with eighteen. Inter Milan, following their achievements in the 2009–10 season, became the first Italian team to have achieved a seasonal treble. It is also the team to have competed uninterruptedly for the most time in the top flight of Italian football, having seen its debut in 1909. All these clubs, along with Lazio, Fiorentina, Roma, and Napoli, are known as the Seven Sisters of Italian football.

Serie A is one of the most storied football leagues in the world. Of the 100 greatest footballers in history chosen by FourFourTwo magazine in 2017, 42 players have played in Serie A, more than any other league in the world. Juventus is the team that has produced the most World Cup champions, with Inter, Roma, and Milan, being respectively third, fourth, and ninth in that ranking.

Serie A, as it is structured today, began during the 1929–30 season. From 1898 to 1922, the competition was organized into regional groups. Because of ever-growing teams attending regional championships, the Italian Football Federation (FIGC) split the CCI (Italian Football Confederation) in 1921, which founded in Milan the Lega Nord (Northern Football League), ancestor of present-day Lega Serie A. When CCI teams rejoined the FIGC created two interregional divisions renaming Categories into Divisions and splitting FIGC sections into two north-south leagues. In 1926, due to internal crises and fascist pressures, the FIGC changed internal settings, adding southern teams to the national division, ultimately leading to the 1929–30 final settlement. Torino was declared champions in the 1948–49 season following a plane crash near the end of the season in which the entire team was killed.

The Serie A Championship title is often referred to as the scudetto (“small shield”) because, since the 1923–24 season, the winning team will bear a small coat of arms with the Italian tricolor on their strip in the following season. The most successful club is Juventus with 36 championships, followed by Inter Milan and AC Milan with 19 and 18 championships respectively. From the 2004–05 season onwards, an actual trophy was awarded to the club on the pitch after the last turn of the championship. The trophy, called the Coppa Campioni d’Italia, has officially been used since the 1960–61 season, but between 1961 and 2004 was consigned to the winning clubs at the head office of the Lega Nazionale Professionisti.

In April 2009, Serie A announced a split from Serie B. Nineteen of the twenty clubs voted in favor of the move in an argument over television rights; the relegation-threatened Lecce had voted against the decision. Maurizio Beretta, the former head of Italy’s employers’ association, became president of the new league.

In April 2016, it was announced that Serie A was selected by the International Football Association Board to test video replays, which were initially private for the 2016–17 season, allowing them to become a live pilot phase, with replay assistance implemented in the 2017–18 season. On the decision, FIGC President Carlo Tavecchio said, “We were among the first supporters of using technology on the pitch and we believe we have everything required to offer our contribution to this important experiment.”