Nilavu Suduvathillai is a 1984 Tamil-language film directed by K. Rangaraj.
The story revolves around Ravi falling in love with Radhika, only to discover she is the daughter of his boss who was testing him under this disguise.
The film stars Sivakumar and Radhika in lead roles, alongside N. Viswanathan and V. Gopalakrishnan.
Production began in 1983 at Prasad Studios, featuring song recording during its launch phase. The February 1984 filming of "Paari Jaadham" is noted.
The film's music was composed by Ilaiyaraaja, marking his first collaboration with Rangaraj. Notably, the song "Naalum En Manam" was later reused twice: as "Prema Ledhani" in a 1988 Telugu film and again in Tamil for Vattara Vazhakku (2023).
The film was released on 18 May 1984.