Ragnarok Battle Offline, or RBO, is a beat 'em up game for Microsoft Windows created by dōjin soft developer French-Bread. The soundtrack is composed by Raito of Lisa-Rec. It is a homage and a spoof of the MMORPG Ragnarok Online created by Korean developer Gravity Corporation.

RBO impressed Gravity Corporation so much that it has been given an official release outside of Japan. Released as Ragnarok Battle, the game has been distributed in Indonesia, Taiwan, Thailand and a deluxe package in Korea which comes with its own gamepad. Level Up! Games also released an English version of RBO available in the Philippines. However, this release is based only on the initial version of RBO, which does not include the expansions released by French-Bread. There is also an unofficial, fan-made English translation patch available for the Japanese version.