Caddoidea superfamily of harvestmen arachnids with a single family Caddidae, which now only contains 2 extant species.

In the subfamily Caddinae, Caddo is found in eastern North America and Japan with the Kuril Islands.

Other similar lineages have previously been grouped together ias a wider concept of Caddidae (After Shear, 1974).

Another genus Hesperopilio, with species from Australia and Chile, has also historically been included in a wider concept of Caddidae, remains in the Suborder Dyspnoi, but has since been transferred to Phalangioidea, although not clearly placed in any established family.

Under the previous wider concept of Caddidae, the complex pattern of biogeography suggested that separation occurred in several steps: during the Neogene (eastern North America and Japan); at the beginning or before the Tertiary (South America and Australia), and during the time of Gondwana (Africa and Australia).