The surname Sheehan, an Anglicisation of the Irish Gaelic Ó Síodhacháin meaning "the peaceful one," is notably common in counties Cork, Kerry, and Limerick, ranking as the 77th most frequent in Ireland. This prominent name has been carried by a diverse range of individuals across entertainment, politics, sports, and science.

Notable figures include acclaimed rock bassist Billy Sheehan (born 1953) and Mark Sheehan (1976–2023), guitarist for The Script, alongside Irish actor Robert Sheehan (born 1988). The surname also distinguishes Pulitzer Prize-winning journalists Neil Sheehan (1936–2021) and Susan Sheehan (born 1937), as well as anti-war activist Cindy Sheehan (born 1957).

Additionally, Harold Leeming Sheehan (1900–1988), a British endocrinologist, famously gave his name to "Sheehan's syndrome," while sports figures like rugby player Dan Sheehan and golfer Patty Sheehan (born 1956) also bear the name.