The Helmet Vanga Euryceros prevostii is a distinctive-looking bird of the vanga family, Vangidae, with a huge arched blue bill. It is the only member of its genus.

It is restricted to lowland and lower montane rainforests in north-east Madagascar.

Sites where it can be found include Marojejy Strict Nature Reserve, the Masoala National Park and Mantadia National Park.

Adults mainly eat large insects, but food items brought to young in the nest may be more varied , including snails, lizards, spiders and crabs.

The binomial of this bird commemorates the French artist Florent Prévost.