Holmiidae occur throughout Baltica (Scandinavia and the eastern seaboard of the Baltic Sea) and Western Laurentia (in the Great Basin of the US and northwestern Canada), and also in Morocco.

Repina (1979) assigned Holmia, Schmidtiellus, Kjerulfia, Elliptocephala, Bondonella, Andalusiana and Holmiella to the Holmiinae, that together with the monotypic Callaviinae comprised the Holmiidae.

Lieberman, who made cladistic analyses of the Olenellina and the included superfamilies, regards Andalusiana an advanced "Nevadioidea", Callavia and Bondonella as Judomioidea, and Elliptocephala and Wanneria stemgroup genera closely related to the common ancestor of the Holmiidae and the Biceratopsidae.

This is interpreted as advanced compared with the arrangement of the simple ocular lobes of Laurentian holmiids, which are separated from the L4 by a prominent axial furrow around the glabellar outline.

Laurentian holmiids (Montezumaspis, Palmetaspis, Grandasinus, Esmeraldina and Holmiella) have unfurrowed ocular lobes separated from L4 by axial furrow.