The 1981 Cincinnati Reds season consisted of the Reds finishing with an overall record of 66–42, giving them the best win–loss record in all of Major League Baseball. However, due to a split-season format caused by a mid-season players' strike, they failed to make the MLB playoffs because they did not finish first in either half of the season; they finished in second place in both halves by scant margins. The Reds finished the first half of the season in second place with a record of 35–21, just one-half game behind the eventual world champion Los Angeles Dodgers, and one-and-a-half games behind the Houston Astros in the second half, in which the Reds were 31–21, good for second place, again. Before the final game of the season against the Atlanta Braves, the team unveiled a banner which said "Cincinnati Reds: Baseball's best record 1981". The Reds were managed by John McNamara and played their home games at Riverfront Stadium.

Offseason

Regular season

Season standings

Record vs. opponents

Notable transactions

Roster

Game log

First half

Second half

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

Awards and honors

Farm system