Julius J. Epstein (August 22, 1909 – December 30, 2000) was an American screenwriter, who had a long career, best remembered for his screenplay, written with his twin brother, Philip, and Howard E. Koch, of the film Casablanca (1942), for which the writers won an Academy Award.

He adapted his play Front Porch in Flatbush into Saturday Night, the first professional musical written by Stephen Sondheim.

His play, But, Seriously (starring Richard Dreyfuss and Tom Poston) would prove to be the last to be staged at Henry Miller's Theatre for more than 30 years, opening on February 27, 1969, and closing after only four performances.

He maintained close ties with Penn State throughout his life (often as a guest lecturer at the film school).

They were noted for their Academy Award-winning Casablanca, written together with Howard Koch and the uncredited Casey Robinson.

They never testified before the committee, but on a HUAC questionnaire, when asked if they ever were members of a "subversive organization," they responded, "Yes.

[1] Epstein shared an Academy Award nomination for the screenplay of Four Daughters, written with Lenore Coffee (with Thyra Samter Winslow contributing to the treatment and Lawrence Kimble contributing to the script), as an adaptation from Frances Hurst's novel, Sister Act.

The picture was a box-office success and won both Bette Davis and Claude Rains Oscar nominations.

After his twin brother's death, Epstein looked out for Philip's son, Leslie, who became a novelist and director of the creative writing program at Boston University.