Oru Naal Koothu (transl. One Day's Ado) is a 2016 Indian Tamil-language romantic comedy drama film directed by Nelson Venkatesan written by Sankardass and Nelson Venkatesan and produced by J. Selva Kumar, featuring Dinesh, Miya, Nivetha Pethuraj (in her debut role), Dev Ramnath, and Riythvika in lead roles. Lingesh, Karunakaran, Ramesh Thilak, Bala Saravanan, and Nagineedu play supporting roles.

The title references the fuss over the wedding day of an Indian marriage. The story is based on the experiences of Nelson Venkatesan himself.

The music was composed by Justin Prabhakaran with cinematography by Gokul Benoy and editing by V J Sabu Joseph. The film released on 9 June 2016 to positive reviews from critics.