OK Jaanu is a 2017 Indian romantic drama film directed by Shaad Ali, story and screenplay by Mani Ratnam. Produced by Mani Ratnam and Karan Johar under their banners Madras Talkies and Dharma Productions respectively. It is an official remake of Mani Ratnam's Tamil film O Kadhal Kanmani starring Dulquer Salmaan and Nithya Menen. The film stars Aditya Roy Kapur and Shraddha Kapoor in the lead roles, portraying a young couple in a live-in relationship in Mumbai with Naseeruddin Shah and Leela Samson play supporting roles as an older couple in the film, portraying the younger couple's landlords. A. R. Rahman composed the film's score and soundtrack. Gulzar is the dialogue writer of this film. Gulzar has also provided the lyrics for the songs in the film.

The first look was released on 29 February 2016. Principal photography commenced in March 2016. The filming has been officially wrapped up on 29 May 2016, with actress Shraddha Kapoor sharing a photo from the film's set.

The film had a worldwide release on 13 January 2017.