| Tonny Koeswoyo | |
| Birth Name: | Koestono Koeswoyo |
| Birth Date: | 19 January 1936 |
| Birth Place: | Tuban, Dutch East Indies |
| Death Place: | Jakarta, Indonesia |
| Instrument: | Vocals, piano, guitar, keyboard |
| Genre: | Rock, pop |
| Occupation: | Musician, singer-songwriter, artist |
| Years Active: | 1962–1987 |
Koestono "Tonny" Koeswoyo (19 January 1936 – 27 March 1987) was an Indonesian rock musician and leader of the music group Koes Plus.[1] Koeswoyo played piano, guitar and keyboard.