multiplayer online casual rhythm game produced by T3 Entertainment. It was originally released in South Korea in 2005, but it has been localized by various publishers around the world including North America which is marketed by Nexon Corporation. Audition Online is free to play but it earns its revenue by selling virtual items such as clothes for the player's avatar.

A person makes a room, chooses whether it is password protected or not, and then people join that room. The 'DJ' (the person who creates the room) then selects a song (e.g. "Beautiful Liar"), sometimes according to the other people's wishes. The DJ also selects a background, such as a basketball court, and then selects the type of game (later explained in this article). The songs have different tempos, with faster ones like "Magic World" (185 bpm) and "Love Mode" (190 bpm) being harder to follow and slower ones like "Don't Give Up/Can't Dismiss/I Cannot Abandon It/Can't Throw It Away" (84 bpm) being easier.

By following the arrows displayed on the screen (with the exception of red Chance arrows, which the player must do the opposite of) and pressing spacebar or the control key on the 4th beat, the player may gain a score of MISS, BAD, COOL, GREAT or PERFECT. The character will dance on the screen respectively to how well the player scored. As the players go on, the number of arrows changes to the level that the player is on. The person who currently has the highest score will be dancing in the front centre. The position is swapped once someone else tops that person's score.