| Masaaki Koike | |
| Position: | Outfielder / Coach |
| Team: | Yokohama DeNA BayStars |
| Number: | 71 |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 15 May 1980 |
| Birth Place: | Yokohama, Kanagawa, Japan |
| Debutleague: | NPB |
| Debutdate: | April 20 |
| Debutyear: | 2001 |
| Debutteam: | Yokohama BayStars |
| Finalleague: | NPB |
| Finaldate: | October 8 |
| Finalyear: | 2013 |
| Finalteam: | Yokohama DeNA BayStars |
| Statyear: | 2013 |
| Statleague: | NPB |
| Stat1label: | Batting average |
| Stat1value: | .243 |
| Stat2label: | Hits |
| Stat2value: | 415 |
| Stat3label: | Home runs |
| Stat3value: | 55 |
| Stat4label: | RBI |
| Stat4value: | 189 |
| Stat5label: | Stolen bases |
| Stat5value: | 6 |
| Teams: | As player
As coach
|
is a professional Japanese baseball player.
Koike played outfield and infield for the Chunichi Dragons (2008–2011) and for the Yokohama DeNA BayStars (2012–2013). Koike announced his retirement on October 1, 2013 and his final at-bat, hit a home run.
In 2014, the Yokohama DeNA BayStars hired Koike as first team batting coach.