Senior synonyms are generally used, except by special decision of the ICZN (see Tyrannosaurus), but junior synonyms cannot be used again for a different genus, even if deprecated. If two or more genera are formally designated and the type specimens are later assigned to the same genus, the first to be published (in chronological order) is the senior synonym, and all other instances are junior synonyms. Junior synonym: A name which describes the same taxon as a previously published name.

Naming conventions and terminology follow the International Code of Zoological Nomenclature. The vast majority of names listed below are sourced to Olshevsky's list, and all subjective determinations (such as junior synonymy or non-dinosaurian status) are based on The Dinosauria, except where they conflict with primary literature. The most authoritative general source in the field is the second (2004) edition of The Dinosauria. The closest is the Dinosaur Genera List, compiled by biological nomenclature expert George Olshevsky, which was first published online in 1995 and was regularly updated until June 2021. There is no official, canonical list of all non-avian dinosaur genera. The list contains 1740 names, of which approximately 1304 are considered either valid dinosaur genera or nomina dubia. Many listed names have been reclassified as everything from true birds to crocodilians to petrified wood.

The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful ( nomen dubium), or were not formally published ( nomen nudum), as well as junior synonyms of more established names, and genera that are no longer considered dinosaurs. This list of dinosaurs is a comprehensive listing of all genera that have ever been considered to be non-avian dinosaurs, but also includes some dinosaurs of disputed status (avian? or non-avian?, where 'avian' refers to the clade Avialae), as well as purely vernacular terms. Dinosaurs can be divided into avian dinosaurs (birds) and non-avian dinosaurs, which are all dinosaurs other than birds. Birds were therefore the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event approximately 66 million years ago. The fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 million years ago their dominance continued throughout the Jurassic and Cretaceous periods. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research.

Mounted skeletons of Tyrannosaurus (left) and Apatosaurus (right) at the AMNHĭinosaurs are a diverse group of reptiles of the clade Dinosauria.

Types of dinosaurs