Alysiines are small braconid wasps that occur throughout the world. The subfamily is quite distinctive, and can be recognised by their large, outwardly-directed and non-over-lapping mandibles, which they use to escape from the puparium (cocoon) of their host. All alysiines are endoparasitoids (internal parasitoids) of flies. The adult female lays her eggs into the egg or larva of the host fly, and her progeny emerge from the host puparium. Alysiines can play an important role in the regulation of pest insects, and one species has been deliberately introduced for the biological control of blowflies. Twenty-one species of alysiines are recorded. Of these, 13 are new species and four are described species from other countries that have not previously been recorded from New Zealand. About three-quarters of the species are endemic, that is, known from nowhere else in the world. Eacb species treatment includes a full synonymy or reference to a full synonymy, a regional bibliography, a diagnosis, list of material examined, collection localities, list of known hosts and bionomics. Appendices include host-parasitoid and parasitoid-host lists for New Zealand records, maps of collection localities, and details of all non-type material examined in this study.