John Henry O'Hara (January 31, 1905 - April 11, 1970) was an American writer.

Born in Pottsville, Pennsylvania, he initially made a name for himself with his short stories and later became a best-selling novelist whose works include Appointment in Samarra and Butterfield 8. He was particularly known for an uncannily accurate ear for dialogue. O'Hara was a keen observer of social status and class differences, and wrote frequently about the socially ambitious.