A ticket is a voucher that indicates that an individual is entitled to admission to an event or establishment such as a theatre, amusement park, stadium, or tourist attraction, or has a right to travel on a vehicle, such as with an airline ticket, bus ticket or train ticket. An individual typically pays for a ticket, but it may be free of charge. A ticket may serve simply as proof of entitlement or reservation. A ticket may be valid for any seat (called "free seating" or "open seating") or for a specific one (called "allocated seating" or "reserved seating").

Members of the public can buy a ticket at a ticket window or counter, called a box office in the entertainment industry (this term is also used for the total receipts), or in some cases online or by telephone. The ticket check may also be located at the box office, or it may be elsewhere. Tickets may also be available from resellers, which typically are commercial enterprises that purchase tickets in bulk and resell them to members of the public, adding a surcharge; consumers buy from resellers for reasons of convenience and availability. The convenience factor relates to being able to obtain tickets locally and being able to make alternate selections on the spot, if the preferred performance is not available. The availability factor relates to the fact that all tickets may have been sold out at the box office, requiring the purchaser to either obtain tickets from the reseller, or not to attend the event (or at least not see the particular performance of choice).

Sometimes, for some bus or train journeys, both free or allocated seating are available, typically with an increased charge for a reserved seat. On some conveyances, a passenger with a free seating ticket on a bus or train carries the risk of having to stand. In contrast, in an arena, cinema, or theatre, a free seating ticket means that a seat is guaranteed, just not a specific one.

Paper or card is generally used, although plastic may be used instead for durability. Some have a barcode or magnetic stripe for keeping simple data stored on them; higher end tickets include chips that store more data and prevent counterfeiting.

A paper ticket often is perforated so it can be separated into two parts, one (the ticket stub) to be kept by the customer, and one to be kept by the ticket controller. Whether or not one can leave and reenter with the customer's ticket stub only varies. It may not be allowed to avoid subsequent use of one ticket by multiple people, or even simultaneous use by giving the ticket to someone before the ticket check (if this is physically possible), but it may also be allowed, e.g., in a movie theatre to allow the stub holder to use the facilities (restroom, telephone, water fountain) or buy, during a movie, a snack or drink before the ticket check and reenter.

A ticket may be printed in advance, or fully or partly printed when issued, or it may be a printed form that is completed in handwriting (e.g., by a train conductor who does not carry a ticket machine, but just a supply of forms and a pen).

Counterfeit tickets are a problem at high-priced concerts and other events, so holograms are used on tickets for the FIFA World Cup, Olympic Games, Super Bowl, and other high-profile events.

Passing back a ticket refers to a fraudulent practice where an attendee, after entering an event using a physical ticket, attempts to give or "pass back" their used ticket to another person outside the venue. This allows the second person to then use the same ticket to gain unauthorized entry, essentially circumventing the entry fee. This scam is particularly prevalent at events where tickets are simply scanned or torn upon entry without further authentication or where re-entry is permitted, allowing the original ticket holder to exit and hand off the ticket.