Campylobacterota are a phylum of Gram-negative bacteria. Only a few genera have been characterized, including the curved to spirilloid Wolinella, Helicobacter, and Campylobacter. Until the 2021 revision of bacterial taxonomy by the ICSP, the entire phylum was classified within the Proteobacteria as the Epsilonproteobacteria.

Helicobacter is a genus of gram-negative bacteria possessing a characteristic helical shape. They were initially considered to be members of the genus Campylobacter, but in 1989, Goodwin et al. published sufficient reasons to justify the new genus name Helicobacter. The genus Helicobacter contains about 35 species.