Naldaviricetes is a class of large double-stranded DNA viruses that infect arthropods. These viruses share a set of homologous genes that encode per os infectivity factors (PIFs), which are essential for oral infection of insect hosts. The class currently includes four recognized families — Baculoviridae, Nudiviridae, Hytrosaviridae, and Nimaviridae — three of which (Baculoviridae, Nudiviridae, and Hytrosaviridae) are grouped within the order Lefavirales. Naldaviricetes was formally established by the International Committee on Taxonomy of Viruses (ICTV) in 2021 to unify these families under a higher-rank taxon based on conserved genomic and structural features. The name Naldaviricetes derives from "Nuclear Arthropod Large DNA Viruses" (NALDVs), a term historically used to describe these four virus families.