The Campeonato Nacional de Liga de Primera División, commonly known simply as Primera División in Spain, and as La Liga in English-speaking countries and officially as LaLiga Santander for sponsorship reasons, stylized as LaLiga, is the men's top professional football division of the Spanish football league system. Administered by the Liga Nacional de Fútbol Profesional, it is contested by 20 teams, with the three lowest-placed teams at the end of each season being relegated to the Segunda División and replaced by the top two teams and a play-off winner in that division.

Since its inception, a total of 62 teams have competed in La Liga. Nine teams have been crowned champions, with Barcelona winning the inaugural La Liga and Real Madrid winning the title a record 35 times, most recently in the 2021–22 season. During the 1940s Valencia, Atlético Madrid and Barcelona emerged as the strongest clubs, winning several titles. Real Madrid and Barcelona dominated the championship in the 1950s, each winning four La Liga titles during the decade. During the 1960s and 1970s, Real Madrid dominated La Liga, winning fourteen titles, with Atlético Madrid winning four. During the 1980s and 1990s Real Madrid were prominent in La Liga, but the Basque clubs of Athletic Club and Real Sociedad had their share of success, each winning two Liga titles. From the 1990s onward, Barcelona have dominated La Liga, winning sixteen titles to date. Although Real Madrid has been prominent, winning ten titles, La Liga has also seen other champions, including Atlético Madrid, Valencia, and Deportivo La Coruña.

According to UEFA's league coefficient rankings, La Liga has been the top league in Europe in each of the seven years from 2013 to 2019 (calculated using accumulated figures from five preceding seasons) and has led Europe for 22 of the 60 ranked years up to 2019, more than any other country. It has also produced the continent's top-rated club more times (22) than any other league in that period, more than double that of second-placed Serie A (Italy), including the top club in 10 of the 11 seasons between 2009 and 2019; each of these pinnacles was achieved by either Barcelona or Real Madrid. La Liga clubs have won the most UEFA Champions League (19), UEFA Europa League (13), UEFA Super Cup (15), and FIFA Club World Cup (7) titles, and its players have accumulated the highest number of Ballon d'Or awards (23), The Best FIFA Men's Player awards including FIFA World Player of the Year (19), and UEFA Men's Player of the Year awards including UEFA Club Footballer of the Year (11).

La Liga is one of the most popular professional sports leagues globally, with an average attendance of 26,933 for league matches in the 2018–19 season. This is the eighth-highest of any domestic professional sports league in the world and the third-highest of any professional association football league in the world, behind the Bundesliga and the Premier League, and above the other two so-called "Big Five" European leagues, Serie A and Ligue 1. La Liga is also the sixth wealthiest professional sports league in the world by revenue, after the NFL, MLB, the NBA, the Premier League, and the NHL.