Ronald Harwood CBE, (born 9 November 1934) is an author, playwright and screenwriter. He is most noted for his plays for the British stage as well as the screenplays for The Dresser (for which he was nominated for an Oscar) and The Pianist, for which he won the 2003 Academy Award for Best Adapted Screenplay. He was nominated for the Best Adapted Screenplay Oscar for The Diving Bell and the Butterfly (2007).

Harwood was born Ronald Horwitz in Cape Town, South Africa, the son of Isobel (née Pepper) and Isaac Horwitz. Harwood moved from Cape Town to London in 1951 to pursue a career in the theatre. He changed his name from Horwitz after an English master told him it was too foreign and too Jewish for a stage actor. After training for the stage at the Royal Academy of Dramatic Art, he joined the Shakespeare Company of Sir Donald Wolfit. From 1953 to 1958, Harwood was Sir Donald's personal dresser. He would later draw on this experience when he wrote the stage play, The Dresser, and the biography: Sir Donald Wolfit CBE: His life and work in the Unfashionable Theatre. In 1959, after leaving the Wolfit company. he joined the 59 Theatre Company for a season at the Lyric Hammersmith.

In 1960, Harwood began a career as a writer and published his first novel, All the Same Shadows in 1961, the screenplay, Private Potter in 1962, and the produced stage play, March Hares in 1964. Harwood continued at a prolific pace penning more than 21 stage plays, and 10 books. He also created more than 16 screen plays, but seldom wrote original material directly for the screen, usually acting as an adapter, sometimes of his own work (notably The Dresser).