The white-booted racket-tail (Ocreatus underwoodii) is a species of hummingbird in the "brilliants", tribe Heliantheini in subfamily Lesbiinae.

[3][4] The white-booted racket-tail, as defined by the International Ornithological Committee (IOC) and the Clements taxonomy, has five subspecies.

[3] However, BirdLife International's Handbook of the Birds of the World (HBW) assigns the name "booted racket-tail" to O. underwoodii and includes those two taxa as subspecies of it.

In all five subspecies of white-booted racket-tail those feathers are straight and do not cross; the flags slightly overlap.

It takes nectar from a variety of plants such as those of genera Palicourea, Clusia, Inga, and Cavendishia.

It makes a tiny cup nest of plant fiber and lichen, typically on a horizontal twig 6 to 8 m (20 to 30 ft) above the ground.

Both male and female white-booted racket-tails give "a diagnostic, descending, thin sweet trill, 'ti-tlee-ee-ee' [and] single 'tsit' and 'trrt' notes.