| Seiji Miyaguchi | |
|---|---|
| Born | 
November 15, 1913 Tokyo, Japan  | 
| Died | April 12, 1985 (aged 71) | 
| Occupation | Actor | 
| Years active | 1933–1985 | 
| Awards | 
Mainichi Film Concours Best Supporting Actor 1955 Seven Samurai  | 
Seiji Miyaguchi (宮口 精二 Miyaguchi Seiji?, November 15, 1913 – April 12, 1985) was a Japanese actor.
Miyaguchi appeared in many films, among them Akira Kurosawa's Seven Samurai (as Kyuzo, the master swordsman), Ikiru as a Yakuza boss from "restaurant row," and Masaki Kobayashi's Kwaidan.
At the age of 71, he succumbed to lung cancer.