Tenchi Muyo! Ryo-Ohki

Tenchi Muyo! Ryo-Ohki (天地無用! 魎皇鬼, Tenchi Muyō! Ryōōki), known as simply Tenchi Muyo! in North America, is a collection of Japanese OVAs created by Masaki Kajishima and animated by AIC. Initially released in 1992, it marked the beginning of the Tenchi Muyo! franchise, composed of several manga, OVAs, TV series, and other related media. The first two OVA series were later licensed and distributed in North America by Pioneer Entertainment, with Funimation taking over the rights for the third series, and later taking over the rights for the first two OVAs. In 2020, Crunchyroll acquired worldwide streaming rights (outside Asia) for the fourth and fifth seasons of the OVA.

Distribution of the first OVA series began in September 1992, releasing six episodes until 1993. The first series was so successful that a seventh special episode was released in September 1993, followed by a second OVA series with six additional episodes that began distribution from September 1994 until September 1995. The second OVA series ended on a cliffhanger, and a third OVA series was distributed in Japan in 2003. The third OVA series continued the Tenchi Muyo OVA storyline with six episodes, followed by a special episode released in September 2005 that concludes the third OVA storyline.

The Ultimate Collection box set release of the first two OVAs from Geneon is one of the few releases from the company to feature THX-certified audio and video.

On October 16, 2015, a fourth OVA series was announced to be in production, the first episode of which was released on November 30, 2016. Subsequent episodes were released with an interval of three months each, and the final part of the series arrived on September 13, 2017. On July 12, 2019, it was announced that a fifth OVA series was in development with Masaki Kajishima again serving as chief director and Hideki Shirane writing and overseeing scripts. Keitaro Motonaga is credited as director. The six-episode OVA series was released from February 28, 2020, to May 28, 2021.