Duffy is a surname of Irish origin that comes from the original Irish name Ó Dubhthaigh, meaning descendant of Dubthach.
Dubthach was an Old Irish first name meaning "black".
Variations include: Duffey, Duffee, Duff, Duthie, O'Duffey, O'Duffy, Duffe, O'Duffe, Dufficy, Doey, Dohey, Doohey, Duhig, Duhigg, Dowey and O'Dowey.
The name originates from Connacht.
It may refer to: