| Motonari Iguchi | |
| Birth Date: | 17 March 1908 |
| Birth Place: | Tokyo |
| Othername: | 井口 基成 |
| Occupation: | pianist |
| Spouse: | Aiko Iguchi |
Motonari Iguchi (17 May 1908, in Tokyo – 29 September 1983, in Tokyo) was a Japanese pianist and educator.
He was influential in the post-war Japanese classical music world and his editions, published by Shunjūsha, are still the standard ones in that country. At the Tokyo Academy of Music Iguchi was a student of Leonid Kreuzer, a German piano instructor known for his powerful playing style, which Iguchi adopted. Later, Motonari Iguchi and his wife, Aiko, went on to become professors at the Tokyo Academy of Music.[1]