Risso's dolphin (Grampus griseus) is a dolphin, the only species of the genus Grampus. Some of the closest related species to these dolphins include: pilot whales (Globicephala spp.), pygmy killer whales (Feresa attenuata), melon-headed whales (Peponocephala electra), and false killer whales (Pseudorca crassidens).

Risso's dolphin is named after Antoine Risso, whose study of the animal formed the basis of the recognised description by Georges Cuvier in 1812. The holotype referred to specimen at the Muséum National d'Histoire Naturelle, an exhibit using preserved skin and skull obtained at Brest, France.

The type and sole species of the genus Grampus refers to Delphinus griseus Cuvier 1812. A proposition to name this genus Grampidelphis in 1933, when the taxonomic status of 'blackfish' was uncertain, and conserving the extensive use of "Grampus" for the 'killer' Orcinus orca", also suggested renaming this species (Grampidelphis exilis Iredale, T. & Troughton, E. le G. 1933). These were recognised as synonyms after publication of the Catalog of Whales (Hershkovitz, 1966).

Another common name for the Risso's dolphin is grampus (also the species' genus), although this common name was more often used for the orca. The etymology of the word "grampus" is unclear. It may be an agglomeration of the Latin grandis piscis or French grand poisson, both meaning big fish. The specific epithet griseus refers to the mottled (almost scarred) grey colour of its body.

The images in this gallery are from two coastal pods off Monterey California.