The 1886 Pittsburgh Alleghenys season was the fifth season of the Pittsburgh Alleghenys franchise.
The Alleghenys finished second in the American Association with a record of 80–57.
Note: G = Games played; AB = At bats; H = Hits; Avg.
= Batting average; HR = Home runs; RBI = Runs batted in
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts