A headliner is the main act in a music, theatre, or comedy performance. Generally, the headliner is the final act in a performance, preceded by the opening act(s).
In ticket sales, the name of the headlining act will generally be the only name or most prominent name on the ticket or advertising vehicle.
In music, the headliner often reserves sole permissions to the name of the tour. Thus, tour names often reflect the name of the latest album or a popular song from the latest album of the headliner. Additionally, the headliner is often the most famous or prominent act in the performance.
In Neo-Burlesque headliners are performers with high reputations whose inclusion in a performance will help to attract a good audience.
The main event is a similar concept in sports.
The term "headliner" dates back to the 1890s.