John O'May is an American-born Australian actor, best known for his stage performances.

O'May was born at Johns Hopkins Hospital in Baltimore, Maryland, one of four children. He grew up with a love of reading and literature. At university he dabbled in theatre, learning acting, stagecraft and building sets. He became a teacher at Patapsco High School, where he himself had attended high school. He taught English literature for two and a half years. He eventually travelled overseas, and after visiting his sister in Australia and ended up staying.

In 1972, O'May auditioned for the role of Ashley Wilkes in Gone with the Wind. He took singing lessons and found an agent. In 1973, he was offered an audition and role in Godspell, replacing John Waters as Judas. He created and performed in the revues Gershwin (with John Diedrich) in 1975 and The 20s and All That Jazz (with Diedrich and Caroline Gilmer) O'May played Che Guevara in the original Australian cast of Evita which opened in Adelaide in April 1980. In the 1980s he was a regular performer with the Melbourne Theatre Company, and played Bobby in Company for the Sydney Theatre Company in 1986 and Captain Corcoran in H.M.S. Pinafore for the Victoria State Opera in 1987.

Film credits include supporting roles in the films Starstruck and Rebel and the television opera The Divorce (2015). In 2000, O’May guest-starred in season 2, episode 11, "Sponsorship and Media Discontent", of the ABC mockumentary, The Games.