Delaney is an Irish surname, an anglicized form of Ó Dubhshláine, usually explained as "descendant of the dark challenger" or "from the black river". It joined the ranks of Irish surnames used as American girls' names in the 1990s alongside Kennedy and Reagan. Delaney peaked at number 169 in 2004, has hovered in the 200s and 300s since and ranks number 242 among girls' names in the United States in 2025.