Robert Bache Smith ( June 4, 1875 – November 6, 1951), usually published as Robert B. Smith, was an American librettist and lyricist. His older brother, Harry B. Smith, was also a successful lyricist and a writer and composer.

Born in Chicago, Smith began his career apprenticing with the famed vaudeville duo Weber and Fields. He most notably wrote the lyrics to “Come Down, Ma Evenin' Star” from Weber and Fields' Twirly Whirly (1902; famously sung by Lillian Russell). He went on to write libretti for operettas and lyrics for musicals, including such works as Fantana (1905), The Spring Maid (1910), Sweethearts (1913), and Angel Face (1919). His last work was The Girl in the Spotlight (credited as Richard Bruce) in 1920. He died in New York City at the age of 76.