Saturday Night is a 1955 musical with music and lyrics by Stephen Sondheim, and a book by Julius J. Epstein, based on the play, Front Porch in Flatbush, written by Epstein and his brother Philip.

Stephen Joshua Sondheim was an American composer and lyricist. Regarded as one of the most important figures in 20th-century musical theater, he is credited with reinventing the American musical. With his frequent collaborators Harold Prince and James Lapine, Sondheim's Broadway musicals tackled unexpected themes that ranged beyond the genre's traditional subjects, while addressing darker elements of the human experience. His music and lyrics were tinged with complexity, sophistication, and ambivalence about various aspects of life.