Peter Alexander Ustinov (born April 16, 1921) is a British actor, writer and dramatist.

He was born in London of Russian parentage. He made his stage début as an actor in 1938, becoming quickly established. After military service in World War II, he began to branch out into writing, and his first major success was with The Love of Four Colonels in 1951. His career as a dramatist continued alongside his acting career, his best-known play being, Romanoff and Juliet (1956). His film roles include Captain Vere in Billy Budd (1962), Lentulus Batiatus in Spartacus (1960), and in several films as Hercule Poirot, a part he first played in Death on the Nile (1978). His autobiography, Dear Me (1977), was well received.

He speaks English, French, German, Italian, Russian, Spanish fluently, as well as some Turkish and modern Greek.