Nenjam Marappathillai (transl. The Heart Never Forgets) is a 1963 Indian Tamil-language paranormal romance film written and directed by Sridhar. The film stars Kalyan Kumar and Devika, with M. N. Nambiar, S. V. Sahasranamam, Nagesh, Padmini Priyadarshini and Manorama in supporting roles. It focuses on a college boy who, while exploring a dilapidated villa, learns all the details about his past life.

The film was conceived by Sridhar based on numerous news reports he read about people claiming to remember their past lives. It was produced by M. S. Kasi under his banner Manohar Pictures, had music composed by Viswanathan–Ramamoorthy, cinematography by A. Vincent and editing by N. M. Shankar. The story was credited to Kasi, and Sridhar's brother C. V. Rajendran worked as the associate director.

Nenjam Marappathillai was released on 2 August 1963. The film received a number of positive reviews but did not succeed commercially, though it later attained cult status in Tamil cinema.