The 1881 Boston Red Caps season was the eleventh season of the franchise.
Regular season
Season standings
Record vs. opponents
Roster
Player stats
Batting
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
Pitching
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