Koutaro Nishiyama
- Title : Koutaro Nishiyama
- Popularity : 7.507
- Known For : Acting
- Birthday : 1991-10-11
- Place of Birth : Kanagawa, Japan
- Homepage : http://www.81produce.co.jp/actor_search/index.php/item?id=98
- Also Known As : Kotaro Nishiyama, 西山 宏太朗, Kōtarō Nishiyama, Koutarou Nishiyama