| Keiji Oyama | |
| Position: | Catcher |
| Birth Date: | 19 November 1980 |
| Bats: | Right |
| Throws: | Right |
| Debutleague: | NPB |
| Debutyear: | 2008 |
| Debutteam: | Hokkaido Nippon-Ham Fighters |
| Statyear: | 2015 |
| Statleague: | NPB |
| Stat1label: | Batting average |
| Stat1value: | .204 |
| Stat2label: | Home runs |
| Stat2value: | 2 |
| Stat3label: | RBI |
| Stat3value: | 30 |
| Teams: | |
Keiji Oyama (小山 桂司; born November 19, 1980) is a Japanese former professional baseball catcher in Japan's Nippon Professional Baseball. He played for the Hokkaido Nippon-Ham Fighters in 2008, the Chunichi Dragons from 2009 to 2011, and for the Tohoku Rakuten Golden Eagles from 2012 to 2015.