O'Leary
O'Leary is an Irish surname meaning “descendant of the clerk” or “descendant of the learned person,” from the Gaelic personal name derived from cleireach.
The #1,607 most common surname in the United States (2010 Census) — about 1 in every 13,827 Americans shares it.
Etymology
O'Leary comes from the Irish Gaelic surname Ó Laoire, traditionally explained as meaning “descendant of Laoire.” The personal name is commonly linked to cleireach, a word for “clerk,” “scribe,” or broadly a learned man. In older surname literature, this association is often treated as the source of the name’s meaning, though the exact history of the personal name itself is not entirely certain.
History
The name is especially associated with Munster, particularly County Cork, where the O'Learys were historically prominent. Like many Irish surnames, it was often anglicized by dropping the apostrophe, producing forms such as Leary and O Leary. The name remains well known in Ireland and among the Irish diaspora.
Origin
Regions
Variant spellings
Fun fact
In older Irish naming practice, a “clerk” could mean not just a writer of documents but a learned scholar or churchman.
From the historical record
“Breheny, . (Breathamh — Irish — a Judge). Oleary, . {Cleireach — Irish — a Clerk). Ward, . (Bhard — Irish — a Bard). Colgan,”
— Special Report on Surnames in Ireland (numerical strength, derivation, distribution)