The Twenty20 Cup is a cricket competition for English and Welsh county clubs.

The Twenty20 format, twenty overs for each team, means a game can be completed in under three hours, making it more palatable for children and families than longer matches. Many games also feature additional activities for the spectators in order to provide more entertainment, such as paddling pools, bouncy castles, themed areas, bowling speed-guns, and prizes for catching a 6 ball. On Finals Day, there is also a performance by a major pop act - Atomic Kitten, Liberty X, Girls Aloud and Sugababes have performed on past Finals Days, and Mutya Buena performed on the 2007 Finals Day at Edgbaston.

Most of the standard rules of cricket are retained, but the emphasis is on fast scoring and fast moving cricket. There are limits on fielding positions, and the boundaries are shorter, to encourage aggressive batting. Batsmen get a Free Hit if the bowler bowls a "No Ball" by overstepping the popping crease. There is also a strict 1 minute 30 second time limit on the amount of time a new batsman has to reach the crease, and in the event of the scores being equal at the end of the overs, there is a "bowl-off", similar to a penalty shoot out, except the bowlers have to bowl at unguarded stumps.

Many games are played in twilight, again to enhance family spectator appeal and to allow attendance after work and school. They also feature numerous musical 'stings' for exciting events, such as the dismissal of a batsman, or the hitting of a boundary.