A box office or box office is a place where tickets are sold to the public for admission to an event. Patrons can transact on a countertop, through a hole in a wall or window, or onto a wicket. By extension, the term is often used, especially in the context of the motion picture industry, as a metonym for the amount of business a particular production, such as a film or stage play, receives. The term is also used to refer to a ticket office in an arena or stadium.

Box office activity can be measured in terms of the number of tickets sold or the amount of money raised from ticket sales. The projection and analysis of these earnings is very important to the creative industries and often a source of interest for fans. This is predominant in the Hollywood film industry.

To determine whether a film has made a profit, it is incorrect to compare the box office receipt directly to the production budget, because the cinema keeps on average almost half of the takings. The split varies from film to film and the percentage for the distributor is usually highest in the first few weeks. It is also common for the distributor to receive a percentage of the gross revenue or a higher percentage of the revenue after deducting the die, whichever is greater.