Tree wētā are wētā in the genus Hemideina of the family Anostostomatidae. The genus is endemic to New Zealand. There are seven species within the genus Hemideina, found throughout the country except lowland Otago and Southland. Because many tree wētā species are common and widespread they have been used extensively in studies of ecology and evolution.

Anostostomatidae is a family of insects in the order Orthoptera, widely distributed in the southern hemisphere. It is named Mimnermidae or Henicidae in some taxonomies, and common names include king crickets in Australia and South Africa, and wētā in New Zealand. Prominent members include the Parktown prawn of South Africa, and the giant wētā of New Zealand.