South Pacific is a musical composed by Richard Rodgers, with lyrics by Oscar Hammerstein II and book by Hammerstein and Joshua Logan. The work premiered in 1949 on Broadway and was an immediate hit, running for 1,925 performances. The plot is based on James A. Michener's Pulitzer Prize–winning 1947 book Tales of the South Pacific and combines elements of several of those stories. Rodgers and Hammerstein believed they could write a musical based on Michener's work that would be financially successful and, at the same time, send a strong progressive message on racism.

The plot centers on an American nurse stationed on a South Pacific island during World War II, who falls in love with a middle-aged expatriate French plantation owner but struggles to accept his mixed-race children. A secondary romance, between a U.S. Marine lieutenant and a young Tonkinese woman, explores his fears of the social consequences should he marry his Asian sweetheart. The issue of racial prejudice is candidly explored throughout the musical, most controversially in the lieutenant's song, "You've Got to Be Carefully Taught". Supporting characters, including a comic petty officer and the Tonkinese girl's mother, help to tie the stories together. Because he lacked military knowledge, Hammerstein had difficulty writing that part of the script; the director of the original production, Logan, assisted him and received credit as co-writer of the book.

The original Broadway production enjoyed immense critical and box-office success, became the second-longest running Broadway musical to that point (behind Rodgers and Hammerstein's earlier Oklahoma! (1943)), and has remained popular ever since. After they signed Ezio Pinza and Mary Martin as the leads, Rodgers and Hammerstein wrote several of the songs with the particular talents of their stars in mind. The piece won the Pulitzer Prize for Drama in 1950. Especially in the Southern U.S., its racial theme provoked controversy, for which its authors were unapologetic. Several of its songs, including "Bali Ha'i", "I'm Gonna Wash That Man Right Outa My Hair", "Some Enchanted Evening", "There Is Nothing Like a Dame", "Happy Talk", "Younger Than Springtime", and "I'm in Love with a Wonderful Guy", have become popular standards.

The production won ten Tony Awards, including Best Musical, Best Score, and Best Libretto, and it is the only musical production to win Tony Awards in all four acting categories. Its original cast album was the bestselling record of the 1940s, and other recordings of the show have also been popular. The show has enjoyed many successful revivals and tours, spawning a 1958 film and television adaptations. The 2008 Broadway revival, a critical success, ran for 996 performances and won seven Tonys, including Best Musical Revival.