Portugal Primeira Liga

Before the Portuguese football reform of 1938, a competition on a round-basis was already being held – the Primeira Liga (Premier League) and the winners of that competition were named "League champions". Despite that, a Championship of Portugal in a knock-out cup format was the most popular and defined the Portuguese champion, although the winners of this competition no longer count as Portuguese football champions.^[]

Then, with the reform, a round-robin basis competition was implemented as the most important of the calendar and began defining the Portuguese champion. From 1938 to 1999, the name Campeonato Nacional da Primeira Divisão (National Championship of the First Division) or just Primeira Divisão (First Division), was used.

Porto won the inaugural edition of the new league championship and successfully defended the title in the next season. In 1939–40 the tournament was expanded from eight to ten clubs, due to an administrative battle between Porto and Académico do Porto, regarding a Regional Championship game that ended with only 43 minutes after the start, and later repeated (which FC Porto won) according to Porto FA decision. FPF came out with a decision to satisfy both clubs, expanding the championship to 10 teams (one more from Porto FA and another from Setúbal FA) and annulling the result from the repetition match. With this decision, FC Porto lost the Regional title and finished in 3rd, Leixões SC became the new regional champion, while Académico was 2nd place. All 3 teams qualified for 1939–40 Primeira Divisão.

In the 1941–42 season, it was decided to expand the championship from eight to ten teams to admit Braga FA and Algarve FA champions (until this season only the top teams from Porto, Coimbra, Lisboa and Setúbal were admitted). Porto finished the regional championship in third place again, which did not grant entry into the Primeira Liga. However, a second expand (from 10 to 12) in the same season was decided, which allowed the club to participate.

After the 1945–46 season, the qualifying system based on regional championships was abandoned and adopted a pyramid system, with relegations and promotions between the 3 tiers. The clubs in Primeira Divisão, Segunda Divisão and Terceira Divisão no longer had to play their district championships on the same season as they had been doing since the first seasons of the Liga. Below is a complete record of how many teams played in each season throughout the league's history;

• 8 clubs: 1934–1939
• 10 clubs: 1939–1940
• 8 clubs: 1940–1941
• 12 clubs: 1941–1942
• 10 clubs: 1942–1945
• 12 clubs: 1945–1946
• 14 clubs: 1946–1971
• 16 clubs: 1971–1987
• 20 clubs: 1987–1989
• 18 clubs: 1989–1990
• 20 clubs: 1990–1991
• 18 clubs: 1991–2006
• 16 clubs: 2006–2014
• 18 clubs: 2014–present

When the Portuguese League for Professional Football took control of the two nationwide leagues in 1999, it was renamed "Primeira Liga" (Premier League).^[]

"The Big Three" (Portuguese: Os Três Grandes) is a nickname for the three most powerful sports clubs in Portugal. With the exception of Belenenses in 1945–46 and Boavista in 2000–01, only three clubs have won the Primeira Liga title – Benfica (38 times), Porto (30) and Sporting CP (20). These three clubs generally end up sharing the top three positions (thus, appearing more frequently in UEFA competitions) and are the only clubs to have played in every season of the competition.

These clubs dominate Portuguese football, and it has become typical for fans to support any of these teams as a "first club", with a local team probably coming afterwards, if at all. The "Big Three" have the highest average attendance ratings every season in Portugal, while many other teams, lacking support from the locals, have suffered from poor attendance. The lack of support for local teams is considered to be one of the main reasons why Portuguese Football registers one of the worst attendance ratings in European Football's best championships, alongside the broadcast of almost all the games on television. In other sports, the rivalry between the big clubs is also considerable and it usually leads to arguments between the fans and players.

Benfica is the club with most league, cup and league cup titles, as well as the most domestic titles (81) and overall titles won (83 or 84, if the Latin Cup is taken into account), including back-to-back European Cup trophies. Porto is the club with most Portuguese Super Cups and international titles won (7).

Sporting CP holds the third place when it comes to the most league and cup titles. Benfica is the only Portuguese club to have won two consecutive European Cup/UEFA Champions League titles, reaching ten European finals: seven European Cups and three UEFA Cup/Europa League, and was runner-up in two Intercontinental Cups. Porto is the only Portuguese club since 1987 to have won any international competition (excluding the UEFA Intertoto Cup), gathering a total of two European Cup/UEFA Champions Leagues, two UEFA Cup/Europa Leagues, one European Super Cup and two Intercontinental Cups and finished runner-up in one European Cup Winner's Cup and three UEFA Super Cups. Sporting won one European Cup Winner's Cup and was runner-up in one UEFA Cup. Apart from the big three, Braga won the last UEFA Intertoto Cup and was runner-up in one UEFA Europa League.

S.C. Braga has finished runner-up once, third three times, and fourth twelve times during the last twenty seasons, not quite breaking into "The Big Three."

Galp Energia acquired the naming rights to the league in 2002, titling the division SuperLiga GalpEnergia. A four-year deal with the Austrian sports betting bwin was announced on 18 August 2005 amid questioning by the other gambling authorities in Portugal (the Santa Casa da Misericórdia and the Portuguese Casinos Association), who claimed to hold the exclusive rights to legal gambling games in Portuguese national territory. After holding the name Liga betandwin.com for the 2005–06 season, the name was changed to bwin LIGA in July 2006.

From the 2008–09 season to the 2009–10 season the league was named Liga Sagres due to sponsorship from Sagres beer. In 2010, they renewed the sponsorship from Sagres, but also got the sponsorship from ZON Multimédia. The league was named Liga ZON Sagres until 2013–14 after the sponsorship agreement between Sagres, ZON (now NOS) and the league ended. In 2015, the league was named Liga NOS until the 2020–21 season. From 2021 to 2023, it was known Liga Portugal Bwin. Since 2023, it is called Liga Portugal Betclic.

Sponsorship names for seasons

• 2002–2005: SuperLiga GalpEnergia
• 2005–2006: Liga betandwin.com
• 2006–2008: bwin LIGA
• 2008–2010: Liga Sagres
• 2010–2014: Liga ZON Sagres
• 2014–2021: Liga NOS
• 2021–2023: Liga Portugal Bwin
• 2023–: Liga Portugal Betclic