The horned grebe or Slavonian grebe is a relatively small and threatened species of waterbird in the family Podicipedidae. There are two subspecies: P. a. auritus, which breeds in Eurasia, and P. a. cornutus, which breeds in North America. The Eurasian subspecies is distributed over most of northern Europe and northern Asia, breeding from Greenland east to the Russian Far East. The North American subspecies spans most of Canada and some of the United States. The species got its name from large patches of yellowish feathers located behind the eyes, called "horns", that the birds can raise and lower at will..

Grebes are aquatic diving birds in the order Podicipediformes. Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Most grebes fly, although some flightless species exist, most notably in stable lakes. The order contains a single family, the Podicipedidae, which includes 22 species in six extant genera.