Box lacrosse, also known as indoor lacrosse and sometimes shortened to boxla, LAX or simply box, is an indoor version of lacrosse played mostly in North America. The game originated in Canada, where it is the most popular version of the game played in contrast to the traditional field lacrosse game. It is played between two teams of six players each, and is traditionally played on an ice hockey rink once the ice has been removed or covered. The playing area is called a box, in contrast to the open playing field of field lacrosse. The object of the game is to use a long handled racket, known as a lacrosse stick, to catch, carry, and pass the ball in an effort to score by ultimately hurling a solid rubber lacrosse ball into an opponent's goal.

At the highest level box lacrosse is represented by the Senior A divisions of the Canadian Lacrosse Association (Western Lacrosse Association of the British Columbia Lacrosse Association and Major Series Lacrosse of the Ontario Lacrosse Association), and the National Lacrosse League.