List of American League pennant winners
Each Major League Baseball (MLB) season, one American League (AL) team wins the pennant, signifying that they are the league's champion and have the right to play in the World Series against the champion of the National League (NL). The pennant was presented to the team with the best win–loss record each year through the 1968 season, after which the AL Championship Series (ALCS) was introduced to decide the pennant winner. The first modern World Series was played in 1903 and, after a hiatus in 1904, has taken place every season except  1994, when a players' strike forced the cancellation of the postseason. The current AL pennant holders are the Houston Astros who won the pennant on October 22, 2021. In 1969, the AL split into two divisions, and the teams with the best records in each division played one another in the five-game ALCS to determine the pennant winner, who received (and continues to receive) the William Harridge Trophy. The trophy featured a golden eagle, the league's emblem, sitting atop a silver baseball and clutching the AL banner. Since 2017, the trophy is all silver with a pennant on  top. The trophy is named for Will Harridge, who was league president from 1931 to 1958. The format of the ALCS was changed from a best-of-five to a best-of-seven format in the 1985 postseason. In 1995, an additional playoff series was added when MLB restructured into three divisions in each league. , the winners of the Eastern, Central, and Western Divisions, as well as the AL Wild Card winner, play in the AL Division Series, a best-of-five playoff to determine the opponents who will play in the ALCS. AL pennant winners have gone on to  win the World Series 66 times, most recently in 2018. The New York Yankees have won 40 AL pennants, winning their first in 1921 and their most recent in 2009. This total is more than twice that of the next-closest team, the Oakland Athletics, who have won 15. They are followed by the Boston Red Sox and the Detroit Tigers, with 14 and 11 pennants won respectively. The Yankees have the most pennants since the introduction of the ALCS in 1969 with 11, followed by the Athletics, Red Sox, and the Baltimore Orioles with 6, 6, and 5 respectively . The Yankees also hold the record for most wins by a pennant-winning team, with their 1998 team winning 114 out of 162 games, finishing 22 games ahead of the Boston Red Sox. The 1954 Cleveland Indians won the most games of any pennant winner under the pre-1969 system, winning 111 out of their 154 games and finishing eight games ahead of the Yankees. The Milwaukee Brewers won the AL pennant in 1982 but later moved to the NL starting in the 1998 season. The only current MLB franchise to have never won a league pennant—and therefore, to have  never appeared in the World Series—is the Seattle Mariners.