Stuart Duncan (born April 14, 1964, Quantico, Virginia, USA) is an American bluegrass musician who plays the fiddle, mandolin, guitar and banjo.

Born in Quantico, Virginia and raised in Santa Paula, California, where he played in the school band, he has been a member of the The Nashville Bluegrass Band since 1985, and is a much-in-demand session musician who has worked with such stars as George Strait, Dolly Parton, Reba McEntire and Barbra Streisand, to name a few.

As a member of the Nashville Bluegrass Band, he won the Grammy Award for Best Bluegrass Album in 1994 and 1996, and was named the Academy of Country Music Fiddle Player of the Year for 1996, 1998, 1999, 2001, and 2004, and Specialty Instrument Player of the Year for 2006. In 2006, he toured with the Mark Knopfler/Emmylou Harris Roadrunning tour and is on the All The Roadrunning and Real Live Roadrunning albums. In 2008, he toured with the Robert Plant/Alison Krauss Raising Sand tour, to much acclaim. He appeared on the Transatlantic Sessions Series 4 broadcast by the [l101418] in September/October 2009.