The 1921 Pittsburgh Pirates season was the 40th season of the Pittsburgh Pirates franchise; the 35th in the National League. The Pirates finished second in the league standings with a record of 90–63. It would be the first that games would be aired on radio via the then new station KDKA-AM to listeners all over Pittsburgh, making that team the first in MLB to employ radio broadcasters for game broadcasts on the then new medium.

Regular season

Season standings

Record vs. opponents

Game log

Opening Day lineup

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

Farm system