Grammonus waikiki, or the Waikiki viviparous brotula, is a species of viviparous brotula found in the Hawaiian Islands where it occurs at depths of around 3–18 metres (9.8–59.1 ft).

This species grows to a length of 7.2 centimetres (2.8 in) SL.

[3] Grammonus waikiki was originally named Microbrotula nigra by Terry Gosline in 1953,[4] but was later removed from Microbrotula by Cohen (1964), who transferred the species to Oligopus, as O. niger.

However, this referral made nigra a secondary homonym of Oligopus niger Risso, 1827 (a synonym of Grammonus ater), necessitating erection of the replacement name Oligopus waikiki.

[5] Later, Oligopus was shown by Nielsen (1999) to be a junior synonym of Pteraclis, so Grammonus was resurrected for all bythitids previously assigned to Oligopus, creating the new combination Grammonus waikiki.