Ceallaigh

Ceallaigh is an Irish surname. It is derived from the given name Ceallach, which is of uncertain meaning, though several possible origins are suggested. One theory links it to ceall, meaning "cell" or "church," implying a connection to a religious order. Another theory connects it to ceallach, meaning "bright-headed" or "contending."

The surname Ceallaigh is most commonly found in Ireland. Variants of the name include Kelly, Kellie, and Kealy, which arose through anglicization of the original Gaelic form. The prefix "Ó" (meaning "descendant of") was traditionally used before the name, resulting in Ó Ceallaigh, though this is often dropped in modern usage, particularly outside of Ireland.

The surname has been borne by numerous individuals throughout Irish history and in the diaspora, contributing to various fields including politics, arts, and sports. The anglicized form Kelly is one of the most common surnames in Ireland.