| Tomoya Yagi | |
| Position: | Pitcher |
| Birth Date: | 7 November 1983 |
| Birth Place: | Hodogaya-ku, Yokohama, Kanagawa, Japan |
| Bats: | Left |
| Throws: | Left |
| Debutleague: | NPB |
| Debutyear: | 2006 |
| Debutteam: | Hokkaido Nippon-Ham Fighters |
| Statyear: | 2016 |
| Stat1label: | Win–loss record |
| Stat1value: | 39-34 |
| Stat2label: | ERA |
| Stat2value: | 3.69 |
| Stat3label: | Strikeouts |
| Stat3value: | 361 |
| Teams: |
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| Awards: | |
| Update: | 6 October 2016 |
Tomoya Yagi (八木 智哉, born November 7, 1983, in Yokohama) is a Japanese former professional baseball pitcher in Japan's Nippon Professional Baseball. He won the Pacific League Rookie of the Year Award in 2006. He played for the Hokkaido Nippon-Ham Fighters, Orix Buffaloes, and Chunichi Dragons from 2006 to 2017.