The Halos were an American doo-wop group active in the 1960s, best known for their hit "Nag". The group's signature sound was characterized by tight vocal harmonies, a prominent feature of the doo-wop genre. Although the band did not achieve sustained commercial success, their contribution to the genre was significant, with "Nag" considered a classic of doo-wop music. Member Al Cleveland went on to become an accomplished songwriter, co-writing several hits for Motown artists, thus adding to the band's overall impact on music history.