Arinthum Ariyamalum (transl. Knowingly and Unknowingly) is a 2005 Indian Tamil-language crime action film written and directed by Vishnuvardhan. It stars Navdeep, Arya, Prakash Raj, and Sameksha, while Adithya, Sangili Murugan, Krishna, and Yog Japee play pivotal roles. The film marks the debut of Arya and the Tamil debut of Sameksha. The film's music was composed by Yuvan Shankar Raja with cinematography by Nirav Shah and editing by A. Sreekar Prasad. "Punnagai Poo" Gheetha, an RJ at a Malaysian radio station THR Raaga, produced the film.

The film was released theatrically on 20 May 2005. It completed a 175-day run at the box office. The film eventually went on to receive Filmfare Award for Best Male Debut – South for Arya. It was remade in Odia as Prema Rutu Asilare in 2006.