Mark O'Brien (July 31, 1949 – July 4, 1999) was an American journalist, poet, and advocate for the disabled.
He has been the subject of two films: Breathing Lessons: The Life and Work of Mark O'Brien, which won an Academy Award in 1997, and The Sessions in which he was portrayed by John Hawkes, a film that won the audience award in the U.S.
Dramatic category at the Sundance Film Festival in 2012.
The Sessions was based on his essay, "On Seeing a Sex Surrogate", which appeared in the Sun magazine in 1990.