Paintball is a sport in which participants use compressed-gas markers to shoot paintballs (roughly marble-sized, .68 caliber, gelatin capsules filled with coloured polyethelene glycol) at other players. Once marked by a paintball, a player is eliminated from the game. There are over 10 million paintball players and thousands of people can attend the major paintball tournaments.

There are three very popular Paintball games. Capture the Flag is the classic schoolyard game with a paintball twist. Teams start on opposing sides and attempt to acquire the opponents' flag while protecting their own. Victory is achieved by being the first team to hang the opponents' flag on the designated location at or near their own starting location. Centre Flag, Similar to Capture the Flag, starts with a single flag at the centre of the field instead of one at each end. The winner is the team that brings the flag to the opponents’ end of the field. With Elimination, the team that eliminates all opposing players wins.

There are various styles of play; Woodsball, paintball's original form, is generally played in a wooded area large enough to hold dozens of players. Woodsball games generally run for more time than speedball games.

Speedball is a faster, closer-quarters game and is played on a field about the size of a basketball court or two. Artificial barriers (bunkers) are placed throughout the field for players to move between and hide behind. The close quarters foster a lot of movement and "bunkering", or running up to an opposing player's bunker and eliminating them from close range. Most national and local tournaments and leagues are built around speedball.

Scenario paintball games are often larger-scale re-enactments of historical battles involving hundreds of people, such as the Battle of Normandy, or modern scenarios such as storming a building and rescuing hostages. Scenario games can last hours or even days, and bigger games often have player re-insertions at set intervals.