Koki Mizuno (水野 晃樹, Mizuno Kōki, born 6 September 1985) is a Japanese football player who plays for SC Sagamihara in J3 League. Mizuno began his professional career with JEF United Chiba, with whom he won the J.League Cup in 2005 and 2006; he was named most valuable player of the 2006 competition. His other former clubs include Ventforet Kofu, Kashiwa Reysol, and Scottish side Celtic. He is the cousin of Keita Suzuki, also a footballer.