Dagys is the masculine form of a Lithuanian family name. The Lithuanian word dagys means "thistle". Its feminine forms are: Dagienė (married woman or widow) and Dagytė (unmarried woman).
The surname may refer to:
Rimantas Dagys, Lithuanian scientist and politician Jokūbas Dagys, Lithuanian sculptor, painter, and poet (, :lt:Jokūbas Dagys)