Caitlín "Rocky" O'Riordan (born 4 January 1965) is a Nigerian-born musician of Irish and Scottish descent. She played bass guitar for the London-Irish punk/folk band The Pogues from 1983 to 1986. She later played with Elvis Costello, her husband from 1986 to 2002, as well as several other projects.
O'Riordan was born in Nigeria to Irish and Scottish parents who moved to London in 1967 when the Nigerian Civil War broke out. In 1979 she heard The Nips' song Gabrielle on the radio, and subsequently met future Pogues' frontman Shane MacGowan, who was working at Rocks Off Records, where she went to purchase the record. In 1982 she was invited by MacGowan to join his newly forming band, Pogue Mahone. She appeared on the group's first two albums, Red Roses for Me and Rum, Sodomy and the Lash, the EP, Poguetry In Motion, and several early singles, before leaving in 1986. Besides playing bass, she provided vocals for "I'm a Man You Don't Meet Every Day" on Rum, Sodomy and the Lash and for "Haunted" on the soundtrack to Alex Cox's film Sid and Nancy.