1891 Boston Reds season

The 1891 Boston Reds baseball team finished the season with a 93–42 record and won the American Association championship in their first season in the new league after the demise of the Players' League. Thus they became only the second team (after the 1889–1890 Brooklyn Bridegrooms) to win championships in two different leagues in successive seasons, as well as the only team to win the pennant every single season of its existence. After the season, the AA also disbanded, and the Reds team folded with the league.

Starters by position
''Note: Pos = Position; G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs; RBI = Runs batted in''

Other batters
''Note: G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs; RBI = Runs batted in''

Starting pitchers
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Other pitchers
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Relief pitchers
Note: G = Games pitched; W = Wins; L = Losses; SV = Saves; ERA = Earned run average; SO = Strikeouts