Irwin Swack (November 8, 1916, in West Salem, Ohio – January 2, 2006) was an American composer of contemporary classical music.

He held degrees from the Cleveland Institute of Music (where he studied violin, graduating with a B.M. in 1939), the Juilliard School, Northwestern University (master's degree), and Columbia University (doctorate). He studied with Henry Cowell (at Columbia University), Gunther Schuller (at Tanglewood), Vittorio Giannini (at Juilliard), and Paul Creston (at Columbia University). His music was recorded on the Centaur, CRS, Opus One, and Living Artist Recordings labels.

His music is published by Carl Fischer, Shawnee Press, Theodore Presser, and Galaxy Music.

His last residence was in Bellmore, New York.