Laurence Kerr Olivier, Baron Olivier, OM ( ; 22 May 1907 - 11 July 1989) was an Academy Award, three-time Golden Globe, BAFTA, two-time honorary Academy Award and five-time Emmy-winning English actor, director, and producer. He is one of the most famous and revered actors of the 20th century, along with his contemporaries John Gielgud, Peggy Ashcroft and Ralph Richardson. Olivier played a wide variety of roles on stage and screen from Greek tragedy, Shakespeare and Restoration comedy to modern American and British drama. He was the first artistic director of the National Theatre of Great Britain and its main stage is named in his honour. He is generally regarded to be the greatest actor of the 20th Century, in the same category as David Garrick, Richard Burbage, Edmund Kean and Henry Irving in their own centuries. Olivier's Academy acknowledgments are considerable—fourteen Oscar nominations, with two wins for Best Actor and Best Picture for the 1948 film Hamlet, and two honorary awards including a statuette and certificate. He was also awarded five Emmy awards from the nine nominations he received.

Olivier's career as a stage and film actor spanned more than six decades and included a wide variety of roles, from Shakespeare's Othello and Sir Toby Belch in Twelfth Night to the sadistic Nazi dentist Christian Szell in Marathon Man and the kindly but determined Nazi-hunter in The Boys from Brazil. A High Church clergyman's son who found fame on the West End stage, Olivier became determined early on to master Shakespeare, and eventually came to be regarded as one of the foremost Shakespeare interpreters of the 20th century. He continued to act until his death in 1989. Olivier played more than 120 stage roles, including: Richard III, Macbeth, Romeo, Hamlet, Othello, Uncle Vanya, and Archie Rice in The Entertainer. He appeared in nearly sixty films, including William Wyler's Wuthering Heights, Alfred Hitchcock's Rebecca, Stanley Kubrick's Spartacus, Otto Preminger's Bunny Lake is Missing, Richard Attenborough's Oh! What a Lovely War, Joseph L. Mankiewicz's Sleuth, John Schlesinger's Marathon Man, Daniel Petrie's The Betsy, Desmond Davis' Clash of the Titans, and his own Henry V, Hamlet, and Richard III. He also preserved his Othello on film, with its stage cast virtually intact. For television, he starred in The Moon and Sixpence, John Gabriel Borkman, Long Day's Journey into Night, The Merchant of Venice, Cat on a Hot Tin Roof, and King Lear, among others.

In 1999, the American Film Institute named Olivier among the Greatest Male Stars of All Time, at fourteen on the list.

He could speak William Shakespeare (I)'s lines as naturally as if he were "actually thinking them", said English playwright Charles C. Bennett, who met Laurence Olivier in 1927. One of Olivier's earliest successes as a Shakespearean actor on the London stage came in 1935 when he played "Romeo" and "Mercutio" in alternate performances of "Romeo and Juliet" with John Gielgud. A young Englishwoman just beginning her career on the stage fell in love with Olivier's Romeo. In 1937, she was "Ophelia" to his "Hamlet" in a special performance at Kronberg Castle, Elsinore, Denmark. In 1940, she became his second wife after both returned from making films in America that were major box office hits of 1939. His film was Wuthering Heights (1939), her film was Gone with the Wind (1939). Vivien Leigh and Olivier were screen lovers in Fire Over England (1937), 21 Days (1940) and That Hamilton Woman (1941). There was almost a fourth film together in 1944 when Olivier and Leigh traveled to Scotland with Charles C. Bennett to research the real-life story of a Scottish girl accused of murdering her French lover. Bennett recalled that Olivier researched the story "with all the thoroughness of Sherlock Holmes" and "we unearthed evidence, never known or produced at the trial, that would most certainly have sent the young lady to the gallows". The film project was then abandoned. During their two-decade marriage, Olivier and Leigh appeared on the stage in England and America and made films whenever they really needed to make some money. In 1951, Olivier was working on a screen adaptation of Theodore Dreiser's novel "Sister Carrie" (Carrie (1952)) while Leigh was completing work on the film version of the Tennessee Williams' play, Streetcar Named Desire, A (1951). She won her second Oscar for bringing "Blanche DuBois" to the screen. Carrie (1952) was a film that Olivier never talked about. George Hurstwood, a middle-aged married man from Chicago who tricked a young woman into leaving a younger man about to marry her, became a New York street person in the novel. Olivier played him as a somewhat nicer person who didn't fall quite as low. A PBS documentary on Olivier's career broadcast in 1987 covered his first sojourn in Hollywood in the early 1930s with his first wife, Jill Esmond (I), and noted that her star was higher than his at that time. On film, he was upstaged by his second wife, too, even though the list of films he made is four times as long as hers. More than half of his film credits come after Entertainer, The (1960), which started out as a play in London in 1957. When the play moved across the Atlantic to Broadway in 1958, the role of "Archie Rice"'s daughter was taken over by Joan Plowright, who was in the film as well. They two married soon after the release of Entertainer, The (1960).