O
- Sherman Obando
- Hiromitsu Ochiai
- Alex Ochoa
- Michihiro Ogasawara
- Koichi Ogata
- Sadaharu Oh
- Akira Ohgi
- Tomokazu Ohka
- Hideki Okajima
- Tom O'Malley
- Naoyuki Omura
- Marion O'Neil
- Steve Ontiveros
- José Ortiz
- Koichi Oshima
- Akinori Otsuka
Read more about this topic: List Of Japanese Baseball Players