Tim O'Brien (b. March 16, 1954 in Wheeling, West Virginia) is an American bluegrass, old time and celtic musician. O'Brien plays guitar, fiddle, mandolin, bouzouki and mandocello and is an accomplished vocalist. He moved to Boulder, Colorado in the 1970s and became part of the music scene there. In 1978 he founded the bluegrass group Hot Rize. Hot Rize had its own offshoot band called Red Knuckles & the Trailblazers.