Sir Peter Alexander Ustinov ( (Y)OO-stin-off; born Peter Alexander Freiherr von Ustinov; 16 April 1921 – 28 March 2004) was a British actor, director and writer. An internationally known raconteur, he was a fixture on television talk shows and lecture circuits for much of his career. Ustinov received numerous accolades including two Academy Awards, a BAFTA Award, three Emmy Awards, and a Grammy Award.

Ustinov received two Academy Awards for Best Supporting Actor for his roles in Spartacus (1960), and Topkapi (1964). He also starred in notable films such as Quo Vadis (1951), The Sundowners (1960), Billy Budd (1962), and Hot Millions (1968). He voiced Prince John and King Richard in the Walt Disney Animated film Robin Hood (1973), and portrayed Agatha Christie's fictional detective Hercule Poirot six times for both film and television.

He also displayed a unique cultural versatility which frequently earned him the accolade of a Renaissance man. Miklós Rózsa, composer of the music for Quo Vadis and of numerous concert works, dedicated his String Quartet No. 1, Op. 22 (1950) to Ustinov.

An intellectual and diplomat, he held various academic posts, and served as a goodwill ambassador for UNICEF and president of the World Federalist Movement (WFM). In 2003, Durham University changed the name of its Graduate Society to Ustinov College, in honour of the significant contributions Ustinov had made as chancellor of the university from 1992 until his death.