The taxonomically challenging cyclostome bryozoan family Horneridae is abundant and diverse in the waters around Aotearoa New Zealand. Using a combination of molecular and morphological approaches, we develop diagnostic characters for species of hornerids, describing 11 species (seven of which are new) in three genera (one of which is new, and one reinstated) from the seafloor around southern New Zealand between Cook Strait at ~42°S and the subantarctic islands at ~55°S. Gracilohornera n. gen. comprises five small, gracile species: the type species G. currieae, as well as G. granolineata n. sp, G. polaris n. sp., G. retrosa n. sp. and G. tumida n. sp. The reticulate genus Retihornera is revived and includes R. squamosa and R. foliacea which are compared with the type genus R. corbicula. In the genus Hornera, we describe the pinnate and palmate branching species H. girvanae n. sp., H. polaris n. sp. and H. querciformis n. sp., comparing them to Hornera robusta. This study is the first to apply molecular techniques for the discrimination of taxa in a globally speciose cyclostome family. In contrast to other regions, hornerid cyclostomes in Aotearoa New Zealand have flourished and diversified; indeed, many more hornerid species may await discovery in New Zealand waters.