Koki Eto (?? ??, Eto Koki, born February 8, 1988) is a flyweight professional boxer from Japan, and a former World Boxing Association Interim Flyweight Champion.
He was born and raised in Okinawa Prefecture and now lives in Tokyo.
Koki is the oldest of the three Eto brothers.
His twin brother Taiki and their younger brother Shingo are all professional boxers training under former World Boxing Association Light Flyweight Champion, Yoko Gushiken.