Betty Comden (May 3, 1917 – November 23, 2006) was an American lyricist, playwright, and screenwriter who contributed to numerous Hollywood musicals and Broadway shows of the mid-20th century. Her writing partnership with Adolph Green spanned six decades: "the longest running creative partnership in theatre history." The musical-comedy duo of Comden and Green collaborated most notably with composers Jule Styne and Leonard Bernstein, as well enjoyed success with Singin' in the Rain, as part of the famed "Freed unit" at Metro-Goldwyn-Mayer.

Betty Comden was born Basya Cohen in Brooklyn, New York in 1917, the younger child of Leo Cohen (originally Astershinsky), a lawyer, and Rebecca (née Sadvoransky) Cohen, an English teacher. Both were Russian immigrants and observant Jews. She had an older brother, Nathaniel ("Nat"), born c. 1915. Basya "attended Erasmus Hall High School and studied drama at New York University, graduating in 1938," according to The New York Times.

In 1938, mutual friends introduced her to Adolph Green, an aspiring actor. Along with the young Judy Holliday and Leonard Bernstein, Comden and Green formed a troupe called the Revuers, which performed at the Village Vanguard, a club in Greenwich Village. Due to the act's success, the Revuers appeared in the 1944 film Greenwich Village, but their roles were so small they were barely noticed, and they returned to New York.

Comden and Green's first Broadway show was On the Town, a 1944 musical about three sailors on leave in New York City that was an expansion of a ballet entitled Fancy Free on which Bernstein had been working with choreographer Jerome Robbins. Comden and Green wrote the book and lyrics, which included sizable parts for themselves (as "Claire" and "Ozzie"). Their next musical, Billion Dollar Baby in 1945, with music by Morton Gould was not a success, and their 1947 show Bonanza Bound closed out-of-town and never reached Broadway.

Comden and Green headed to California and soon found work at MGM. They wrote the screenplays for Good News and The Barkleys of Broadway (which reunited Fred Astaire and Ginger Rogers), and then adapted On the Town for Frank Sinatra and Gene Kelly, scrapping most of Bernstein's music at the request of Arthur Freed, who did not care for the Bernstein score. The duo reunited with Gene Kelly for their most successful project, the classic Singin' in the Rain, about Hollywood in the final days of the silent film era. Comden and Green provided the story and screenplay; the songs were hits from the late 1920s and early 1930s by Arthur Freed and Nacio Herb Brown.

They followed this with another hit, The Band Wagon, in which the characters of Lester and Lily, a husband-and-wife musical-writing team, were patterned after themselves. As with Singin' in the Rain, the real-life team did not write the songs. They were Oscar-nominated twice, for their screenplays for The Band Wagon and It's Always Fair Weather. Both films also received Screen Writers Guild Awards; On the Town did too.

Comden and Green's stage work of the 1950s included Two on the Aisle, starring Bert Lahr and Dolores Gray, with music by Jule Styne; Wonderful Town, a musical adaptation of the play My Sister Eileen, with music by Bernstein; and Bells Are Ringing, which reunited them with Judy Holliday and Jule Styne. The score, including the standards "Just in Time", "Long Before I Knew You", and "The Party's Over", proved to be one of their richest.

The duo contributed additional lyrics to the 1954 musical Peter Pan, translated and streamlined Die Fledermaus for the Metropolitan Opera, and collaborated with Styne on songs for the play-with-music Say, Darling. In 1958, they appeared on Broadway in A Party with Betty Comden and Adolph Green, a revue that included some of their early sketches. It was a critical and commercial success, and they brought an updated version back to Broadway in 1977.