Takehito Koyasu is a Japanese voice actor. Koyasu is part of the voice actor quartet Weiß consisting of Weiß Kreuz voice castmates Shinichiro Miki, Tomokazu Seki, and Hiro Yūki. He used to work for Production Baobab but is now the head of T's Factory, a voice actor company he founded in 1998.

Koyasu is known for his deep, smooth voice, which often lands him in roles that are either villains or lonely bishōnen. Recently, though (as in the cases of Mitsurugi Hanagata from Saber Marionette J, Ryo Kuroyanagi from Yakitate!! Japan, Bobobo-bo Bo-bobo, and Kei Itoshiki from (Zoku) Sayonara, Zetsubou-Sensei) he has been voicing more and more lively/humorous characters. According to Hisaya Nakajo, the manga artist of the series Hana-Kimi, the character of Masao Himejima was designed with Koyasu's voice in mind; the voice actor ended up voicing this character in the series' drama CDs.