Oklahoma! is the first musical written by the duo of Rodgers and Hammerstein. The musical is based on Lynn Riggs's 1931 play, Green Grow the Lilacs. Set in farm country outside the town of Claremore, Indian Territory, in 1906, it tells the story of farm girl Laurey Williams and her courtship by two rival suitors, cowboy Curly McLain and the sinister and frightening farmhand Jud Fry. A secondary romance concerns cowboy Will Parker and his flirtatious fiancée, Ado Annie.

Musical theatre is a form of theatrical performance that combines songs, spoken dialogue, acting and dance. The story and emotional content of a musical – humor, pathos, love, anger – are communicated through words, music, movement and technical aspects of the entertainment as an integrated whole. Although musical theatre overlaps with other theatrical forms like opera and dance, it may be distinguished by the equal importance given to the music as compared with the dialogue, movement and other elements. Since the early 20th century, musical theatre stage works have generally been called, simply, musicals.