Isai (transl. Music) is a 2015 Indian Tamil-language musical psychological thriller drama film film co-produced, written, directed and composed by S. J. Surya, making his comeback as a director after a 10-year hiatus since 2005. The film stars himself in the lead role with debutant Sulagna and Sathyaraj. The story is about the tiff between Vetriselvan (Sathyaraj) and A. K. Shiva (Surya), the two music composers in the film industry. The film marked the debut of S. J. Surya, as a music director, with cinematography handled by Soundararajan and editing by K. M. Riyas.
