| Masato Koga 古賀 正人 | |
| Fullname: | Masato Koga |
| Birth Date: | 22 May 1970 |
| Birth Place: | Shizuoka, Shizuoka, Japan |
| Position: | Midfielder |
| Youthyears1: | 1986–1988 |
| Youthclubs1: | Shimizu Commercial High School |
| Youthyears2: | 1989–1992 |
| Youthclubs2: | Hosei University |
| Years1: | 1993–1996 |
| Clubs1: | Yokohama Marinos |
| Caps1: | 27 |
| Goals1: | 1 |
| Years2: | 1997–2000 |
| Clubs2: | Sagan Tosu |
| Caps2: | 105 |
| Goals2: | 11 |
| Years3: | 2001–2006 |
| Clubs3: | Sagawa Express Chukyo |
| Totalcaps: | 132 |
| Totalgoals: | 12 |
is a former Japanese football player. His elder brother Takuma is also a former footballer.
Koga was born in Shizuoka on May 22, 1970. After graduating from Hosei University, he joined the Yokohama Marinos in 1993. He debuted in 1995 and he played many matches as an offensive midfielder. The club also won the league championship in 1995. However he did not play in any matches in 1996 and he moved to the Japan Football League club Sagan Tosu in 1997. He became a regular player and the club was promoted to the J2 League in 1999. In 2001, he moved to the Regional Leagues club Sagawa Express Chukyo. He retired at the end of the 2006 season.
| Club performance | League | Cup | League Cup | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Club | League | Apps | Goals | Apps | Goals | Apps | Goals | Apps | Goals | |
| Japan | League | Emperor's Cup | J.League Cup | Total | |||||||
| 1993 | Yokohama Marinos | J1 League | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 1994 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
| 1995 | 25 | 1 | 2 | 0 | colspan="2" | - | 27 | 1 | |||
| 1996 | 2 | 0 | 0 | 0 | 3 | 0 | 5 | 0 | |||
| 1997 | Sagan Tosu | Football League | 26 | 2 | 3 | 1 | 6 | 0 | 35 | 3 | |
| 1998 | 22 | 5 | 3 | 0 | colspan="2" | - | 25 | 5 | |||
| 1999 | J2 League | 29 | 4 | 2 | 0 | 1 | 0 | 32 | 4 | ||
| 2000 | 28 | 0 | 2 | 1 | 2 | 0 | 32 | 1 | |||
| Total | 132 | 12 | 12 | 2 | 12 | 0 | 156 | 14 | |||