Horopeta is a genus of baleen whale from the Late Oligocene (Chattian) Kokoamu Greensand of New Zealand.

Horopeta can be distinguished from other balaenomorphs in the following characters: base of frontal sloping moderately from skull midline; parietal considerably exposed at sagittal crest; parietal largely exposed at sagittal crest; unfused and short posterior process of periotic and tympanic bulla; prominent superior process of periotic; presence of elliptical foramen and sigmoidal cavity in tympanic bulla; unfused and short posterior processes of periotic and tympanic bulla; a distinct pedicle plate situated in fovea epitubaria; presence of horizontal cleft, elliptical foramen, and sigmoidal cavity in tympanic bulla.

[1] Initial cladistic analysis recovered Horopeta as either a basal balaenomorph or a basal cetotheriid, although the describers noted that the juvenile nature of the holotype might influence its cladistic position within Chaeomysticeti.

[1][2][3] Based on the structure of the jaw, Horopeta was one of the earliest chaeomysticetes capable of gulp-feeding as in extant mysticetes.

[1] The same deposits that yielded Horopeta have also yielded the primitive odontocetes Awamokoa, Austrosqualodon, Otekaikea, and Waipatia, the eomysticetids Matapanui, Tohoraata, Tokarahia, and Waharoa, and the balaenomorphs Mauicetus and Whakakai.