Dacus may refer to:
- Dacus, a genus of tephritid or fruit flies in the family Tephritidae
- Adjectival form of Latin Dacia, ancient kingdom in Central and South-Eastern Europe
- Adjectival form of Latin Dacia (Denmark) , medieval Latin name for Denmark or the Nordic region in general
- Dacus, Latinised name of the mediaeval English Denys family, of Danish origin
- Joseph A. Dacus, American author
- Lucy Dacus, American indie rock singer and guitarist