Chalcid wasps (, from Greek khalkos 'copper', for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, meaning the vast majority have yet to be discovered and described. The name "chalcid" is often confused with the name "chalcidid", though the latter refers strictly to one constituent family, the Chalcididae, rather than the superfamily as a whole; accordingly, most recent publications (e.g.,) use the name "chalcidoid" when referring to members of the superfamily.

Most chalcid wasps are parasitoids of other insects, though other life styles are known, with the herbivorous fig wasps acting as pollinators. Various species are used as biological pest control agents or in scientific research.