In sports, an ejection (also known as dismissal, sending-off, disqualification, or early shower) is the removal of a participant from a contest due to a violation of the sport's rules. The exact violations that lead to an ejection vary depending upon the sport, but common causes for ejection include unsportsmanlike conduct, violent acts against another participant that are beyond the sport's generally accepted standards for such acts, abuse against officials, violations of the sport's rules that the contest official deems to be egregious, or the use of an illegal substance to better a player's game. Most sports have provisions that allow players to be ejected, and many allow for the ejection of coaches, managers, or other non-playing personnel. In sports that use penalty cards, a red card is often used to signal dismissals.

The decision to eject a participant usually lies with one or more officials present at the contest (e.g., referees or umpires). In addition to removal from the contest, many sports leagues provide additional sanctions against participants who have been ejected, such as monetary fines or suspensions from future contests.

When the offender is ejected, they must leave the immediate playing area; in most cases, this means going to the locker room or other part of the venue out of sight of the playing area, or in extreme cases, leaving the facility grounds. In many youth sports leagues, ejected players are required to stay with their coach in the team area, or at least be supervised by an adult at whatever location the player is required to go. If a participant refuses to cooperate with an ejection, additional sanctions may be levied, such as forfeiture of the contest, monetary fines, or suspensions. Rarely, outside actions and sanctions from law enforcement authorities may be required.