Warne Marion Marsh (October 26, 1927 – December 18, 1987) was an influential American tenor saxophonist known for his intricate improvisational style and association with the "Cool School" of jazz. Born in Los Angeles, California, Marsh hailed from an artistic family; his father, Oliver T. Marsh, was a Hollywood cinematographer, and his mother, Elizabeth, was a violinist. He was also related to actresses Mae Marsh and Marguerite Marsh.

Marsh's musical journey was significantly shaped by his studies with pianist Lennie Tristano, whose philosophy of improvisation—emphasizing the purity of the long line and avoiding clichéd licks—profoundly influenced Marsh's approach. Alongside Lee Konitz, Marsh became one of Tristano's most successful students, known for his cool-toned yet rhythmically complex and harmonically sophisticated playing.

In the 1940s, Marsh played with Hoagy Carmichael's Teenagers and, after serving in the U.S. Army, joined Buddy Rich's band in 1948. His collaborations with Tristano and Konitz from 1949 to 1952 produced recordings that are still celebrated for their seamless horn unisons. Marsh's career included periods of teaching and leading his own groups, as well as a notable stint with the ensemble Supersax in the 1970s, where he orchestrated Charlie Parker solos.

Marsh's discography, though somewhat scattered due to recordings on small labels, has grown in recognition posthumously, influencing a new generation of jazz musicians, including Mark Turner. His unique sound, characterized by a light tone and vertical improvisation, continues to be revered within jazz circles.

Tragically, Warne Marsh passed away from a heart attack while performing at Donte's club in Los Angeles in 1987, leaving behind a legacy as a cult figure in jazz. He is interred at Forest Lawn Memorial Park in Glendale, California. A documentary titled "Warne Marsh: An Improvised Life," directed by his son K.C. Marsh, is being made to honor his contributions to music.