Mark Kozelek (born 1967 in Massillion, Ohio) is an American singer/songwriter and frontman of Sun Kil Moon and Red House Painters.

Originally a lynchpin of the sadcore movement in alternative rock with Red House Painters, Kozelek's harrowing autobiographical lyrics gave unflinchingly detailed accounts of pain, despair and loss while the lengthy accompanying music was slow, intense, dissonant and bleak. As time has passed, his music has become more acoustic and folk-inflected, while his lyrics now seem obsessed with memory, geography and those who died before their natural time, arguably best demonstrated on Sun Kil Moon's Ghosts of the Great Highway.

Kozelek was a troubled child, born in Ohio and allegedly addicted to drugs by the age of 10. He entered rehab a few years later and clung to music and songwriting to get him through the days.