Koichiro Koga (古賀 幸一郎, Koga Kōichirō, born (1984-08-30)30 August 1984) is a retired Japanese male volleyball player.

He was a part of the Japan men's national volleyball team.

On club level, he played for Toyoda Gosei Trefuerza and then Wolf Dogs Nagoya.

[3] Koga has younger brother, Taichiro Koga, who is a part of Japan men's national volleyball team as the same position.

This biographical article relating to volleyball in Japan is a stub.