| 1955 NPB season | |
|---|---|
| League | Nippon Professional Baseball |
| Sport | Baseball |
| Central League Pennant | |
| League champions | Yomiuri Giants |
| Runners-up | Osaka Tigers |
| Season MVP | Tetsuharu Kawakami (YOM) |
| Pacific League Pennant | |
| League champions | Nankai Hawks |
| Runners-up | Nishitetsu Lions |
| Season MVP | Tokuji Iida (NAN) |
| Japan Series | |
| Champions | Yomiuri Giants |
| Runners-up | Nankai Hawks |
| Finals MVP | Takehiko Bessho (YOM) |
The 1955 Nippon Professional Baseball season was the sixth season of operation of Nippon Professional Baseball (NPB). This season featured the worst statistical season by winning percentage in NPB history, a .231 winning percentage set by the Taiyo Whales. This season also saw the most wins in a single season by a single team in NPB history, with the Nankai Hawks winning a record 99 games.
The Yomiuri Giants defeated the Nankai Hawks in the Japan Series, 4 games to 3, marking the Giants' 4th NPB championship, all of which to this point had come against the Hawks.