Coronaviridae is a family of enveloped, positive-strand RNA viruses which infect fish, amphibians, birds, and mammals. The group includes the subfamilies Letovirinae, Orthocoronavirinae, and Pitovirinae. The members of the subfamily Orthocoronavirinae are known as coronaviruses.

The viral genome is 26–32 kilobases in length. The particles are typically decorated with large (~20 nm), club- or petal-shaped surface projections (the "peplomers" or "spikes"), which in electron micrographs of spherical particles create an image reminiscent of the solar corona.