Long Day's Journey into Night is a 1962 American drama film directed by Sidney Lumet, adapted from Eugene O'Neill's Pulitzer-winning play of the same name. It stars Katharine Hepburn, Ralph Richardson, Jason Robards, and Dean Stockwell. The story deals with themes of addiction and the resulting dysfunction of the nuclear family, and is drawn from O'Neill's own experiences. It was shot at Chelsea Studios in New York, with exteriors filmed on City Island.

The film won Best Actor (for Richardson) and Best Actress (for Hepburn) at the Cannes Film Festival and was named by the National Board of Review as one of the Top Ten Films of 1962. Hepburn's performance earned her an Oscar and Golden Globe nomination for Best Actress.

O'Neill's play was adapted to film again in 1996, directed by David Wellington.