Mark O'Connor (born August 5, 1961) is an American violinist and composer whose music combines bluegrass, country, jazz and classical.
O'Connor has released 45 albums, of mostly original music, over a 45-year career. He has recorded and performed mostly his original American Classical music for decades. He is also an expert at traditionally-based fiddle and bluegrass music. He has appeared on 450 albums, composed nine concertos and has put together groundbreaking ensembles. His mentors have included Benny Thomasson who taught O'Connor to fiddle as a teenager, French jazz violinist Stéphane Grappelli with whom O'Connor toured as a teenager, and guitarists Chet Atkins, Doc Watson and Steve Morse.