The monogeneric subfamily Calesinae is a small group of minute chalcidoid wasps that are parasitoids of whiteflies. They are native to the Australian region and Neotropics, though one species, Cales noacki Howard, has been imported into North America and the Mediterranean for control of the woolly whitefly, Aleurothrixus floccosus (Maskell) (Hemiptera: Aleyrodidae) on citrus. Historically, the Calesinae have been included within the Trichogrammatidae and Mymaridae, though they are most often associated with the Aphelinidae. The subfamily is currently unplaced within the superfamily Chalcidoidea. Here we present a detailed morphological examination of the three described species in addition to a newly discovered species from New Zealand. The apparently apomorphic characteristics of the head, mouthparts, antennae, wings, mesosoma and genitalia, are weighed against characteristics suggesting affinities with established chalcidoid families. We conclude that the Calesinae are sufficiently unique to warrant family-level status, the Calesidae.