Rivoli's hummingbird (Eugenes fulgens), also known as the magnificent hummingbird, is a species of hummingbird in the "mountain gems", tribe Lampornithini in subfamily Trochilinae. It is found in El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and the United States.
Rivoli's hummingbird is about 11 to 14 cm (4.3 to 5.5 in) long, with males typically a little larger than females. It has a wingspan of 18 centimetres (7.1 in). Of the hummingbirds found in the United States, Rivoli's hummingbird is one of the two largest species, rivaled in size only by the blue-throated hummingbird. The black bill is long and straight to slightly decurved. Both sexes look very dark unless the sun catches the iridescence of the plumage and the brilliant colors flash in the sunlight. During much of the year the species is in the "definitive basic" breeding plumage described below. It has a protracted molt between that plumage and the duller non-breeding appearance. There are some minor clinal variations in bill length and the color of the vent area.