O’Riordan is a surname of Irish origin.
Famous people with this surname include:
Aodhán Ó Ríordáin (born 1976), Irish politician
Brendan O'Riordan (contemporary), Irish professional football player
Brian O'Riordan (born 1981), Irish professional rugby player
Cait O'Riordan (born 1965), British rock musician
Conal Holmes O'Connell O'Riordan (1874–1948), Irish dramatist and novelist
Dolores O'Riordan (born 1971), Irish singer and songwriter
Don O'Riordan (born 1957), Irish professional football player and coach
Eugene O'Riordan (contemporary), Irish author and professor of mathematics
Gerry O'Riordan (fl. mid-20th century), Irish hurler
Julius O'Riordan (born 1966), British DJ
Mark O'Riordan (born 1980), Irish hurler
Michael O'Riordan (1917–2006), Irish communist; founder of the Communist Party of Ireland
Mossy O'Riordan (fl. mid-20th century), Irish hurler
Robert O'Riordan (born 1943), Canadian author
Seán Ó Ríordáin (1917–1977), Irish language poet