Fumontana deprehendor Copyright © M. Hedin
Most Triaenonychidae are from three to five millimeters long, although some species from South Africa can be only 1 mm long. Some species in the subfamily Adaeinae are almost 10 mm long. Legs are almost always short, measuring 4-12 mm. The armed pedipalps are large, and much stronger than the legs. 
The Triaenonychidae should probably split into at least two families. The genera from the Australian region are considered Triaenonychidae sensu stricto, and may include the strange Synthetonychiidae; the northern species should be grouped with Travuniidae .
The name of the type genus Triaenonyx is combined from Ancient Greek τρίαινα (triaina, "trident, fish spear") and ὄνυξ (onyx, "claw").
- Adaeinae Pocock, 1902
- Soerensenellinae Forster, 1954
- Triaenobuninae Pocock, 1902
- Triaenonychinae Sørensen, 1886