[4] Two extinct genera, Xanthorhysis and Afrotarsius, are considered to be close relatives of the living tarsiers, and are generally classified within Tarsiiformes, with the former grouped within family Tarsiidae, and the latter listed as incertae sedis (undefined).

[3] Omomyids are generally considered to be extinct relatives, or even ancestors, of the living tarsiers, and are often classified within Tarsiiformes.

[7][8] Likewise, Carpolestidae is often classified within the order Plesiadapiformes, a very close, extinct relative of primates.

Even the placement of Tarsiiformes within suborder Haplorhini, as a sister group to the simians (monkeys and apes), is still debated.

[3] As haplorhines, they are more closely related to monkeys and apes than to the strepsirrhine primates, which include lemurs, galagos, and lorises.