List of World Series champions

The World Series is the annual championship series of Major League Baseball (MLB) and concludes the MLB postseason. First played in 1903, the World Series championship is a best-of-seven playoff and is a contest between the champions of baseball's National League (NL) and American League (AL). Often referred to as the "Fall Classic", the modern World Series has been played every year since 1903 with two exceptions: in 1904, when the NL champion New York Giants declined to play the AL champion Boston Americans; and in 1994, when the series was canceled due to the players' strike. The best-of-seven style has been the format of all World Series except in 1903, 1919, 1920, 1921, when the winner was determined through a best-of-nine playoff. Although the large majority of contests have been played entirely during the month of October, a small number of Series have also had games played during September and November. The Series-winning team is awarded the Commissioner's Trophy. Players, coaches and others associated with the team are generally given World Series rings to commemorate their victory; however, they have received other items such as pocket watches and medallions in the past.

A total of 121 World Series have been contested through 2025, with the AL champion winning 68 and the NL champion winning 53. The New York Yankees of the AL have played in 41 World Series, winning 27 – the most championship appearances and most victories by any MLB team. The Dodgers and the Yankees are tied for the most losses with 14 each. The St. Louis Cardinals have won 11 championships, the most among NL clubs and second-most all-time behind the Yankees. The Dodgers have represented the NL the most in the World Series with 23 appearances. The Seattle Mariners are the only MLB franchise that has never appeared in a World Series; the Milwaukee Brewers, San Diego Padres, Tampa Bay Rays, and Colorado Rockies have all played in the Series but have never won it, with the Padres and the Rays appearing twice. The Los Angeles Angels and Washington Nationals are the only teams who have won their only World Series appearance, and the Miami Marlins are the only team with multiple World Series appearances and no losses with two. The Toronto Blue Jays are the only franchise from outside the United States to appear in and win a World Series, winning in 1992 and 1993. The Houston Astros are the only franchise to have represented both the NL (2005) and the AL (2017, 2019, 2021, 2022), winning the Series in 2017 and 2022. The 1919 and 2017 World Series were both marred with cheating scandals: the Black Sox Scandal and the Houston Astros sign stealing scandal. The most recent World Series champions are the Los Angeles Dodgers.

The last team to repeat as champions were the Dodgers in 2025. Two World Series matchups (in 1982 and 2005) have no current possibility of a rematch due to one of the contending teams switching to the opposing league – the Milwaukee Brewers moved to the NL in 1998, and the Houston Astros moved to the AL in 2013.