Finnigan is a spelling of Finnegan, an Irish surname from O Fionnagain, "descendant of Fionnagan", a pet form of fionn, so it means "fair" or "white"; James Joyce's Finnegans Wake made the surname famous, and the first name borrows the nickname Finn. In the United States Finnigan ranked number 7685 in 2000, peaked at number 1591 in 2016 and was given to 50 boys in 2025, which places it at number 2615.