Risa Kimura (木村 理沙, Kimura Risa, born July 9, 1965), better known by her pen name Yun Kōga (高河 ゆん, Kōga Yun) is a Japanese manga artist.

She debuted in a commercial magazine with the original work Metal Heart (serialized in Kobunsha's Comic VAL from November 1986).

However, the later disbanding of a dōjin circle, Yajō Teikoku, she had founded with Maki Chikura, led to her taking numerous breaks from her commercial works.

During her years in middle school, she had been a fan of Masami Kurumada's manga series Ring ni Kakero, Fūma no Kojirō, Saint Seiya (all serialized in Weekly Shōnen Jump) and B't X (serialized in Monthly Shōnen Ace), sending Kurumada numerous fan letters asking to meet him, after which Kurumada finally agreed, inviting her to his workplace.

In 2007, she contributed the character designs to the Sunrise anime series, Mobile Suit Gundam 00.