In baseball and softball statistics, an error is an act, in the judgment of the official scorer, of a fielder misplaying a ball in a manner that allows a batter or baserunner to advance one or more bases or allows a plate appearance to continue after the batter should have been put out. The term error is sometimes used to refer to the play during which an error was committed.

In the game of baseball, the official scorer is a person appointed by the league to record the events on the field, and to send the official scoring record of the game back to the league offices. In addition to recording the events on the field such as the outcome of each plate appearance and the circumstances of any baserunner's advance around the bases, the official scorer is also charged with making judgment calls that do not affect the progress or outcome of the game. Judgment calls are primarily made about errors, unearned runs, fielder's choice, the value of hits in certain situations, and wild pitches, all of which are included in the record compiled. This record is used to compile statistics for each player and team. A box score is a summary of the official scorer's game record.