The umpire is an important sports official in a number of different sports competitions. Essentially, an umpire functions as the final authority in making sure that the rules of the sport are being followed. The umpire is often called upon to make judgment calls on whether or not a specific play is in accordance with the rules of the game, as well as exercise authority to limit the participation of players in the event of conduct that is considered illegal or inappropriate. The roles of umpire and referee are essentially the same, with the use of one term or another based on the sport in question.

In the United States, there are several sports that prefer the use of the term umpire as opposed to calling the sports officials who exercise control over the game by the designation of referees. One of the most common examples is within the realm of baseball. Both major and minor baseball leagues and individual clubs refer to their sports officials as an umpire. The use of the term also is common in Little League use, as well as high school and college level baseball.

Rather than having one central umpire, it is more common to have several umpires that cover various parts of the field, ensuring that any activity that takes place during the game is within the rules and regulations associated with both the general sport and the particular level or league. The number of umpires that participate in a single game may vary, based on the level of the competition. A typical game will employ two or three umpires, but a championship game may have as many as six persons filling the role of umpire at various sections of the playing field, as well as at home plate.

In other parts of the world, the umpire is also a designated authority that ensures the game progresses fairly and within the rules of the competition. Australian football is once such example. Under the rules of Australian football, a single game will include the supervision of several different persons who function as an umpire. There is usually between one and three persons designated as field umpires, two persons who function as boundary umpires, and an umpire that is stationed at each of the two goals.