Hoilungidae is a placozoan family comprising Hoilungia and other currently undescribed taxa.

Named in 2022, it is believed to be sister to Cladtertiidae, and corresponds to Clades IV, V and VII.

[1] Previous studies established these clades on the basis of phylogenomic data.

The latter two are believed to encompass multiple species each, although the 2022 study establishing the structure of the family only mapped a single lineage of each.

[1] The following phylogeny follows Eitel et al., 2024, and is based on complete mitochondrial genomes.