Lycopodioideae is a subfamily in the family Lycopodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I).

The oldest fossils of modern members of the subfamily date to the Early Cretaceous.

The main stems are indeterminate and of various forms, including rhizomatous, creeping, trailing and climbing.

[4] Although other genera now placed within the family (in particular Huperzia, published in 1801[5]) had been described, until the mid-1900s, Lycopodium was often the only genus recognized.

Work by Josef Holub and Benjamin Øllgaard in the 1980s established three clear divisions within the family.

Three subfamilies, including Lycopodioideae, were first suggested by Warren Wagner Jr. and Joseph Beitel in 1992, but were not validly published under the International Code of Botanical Nomenclature as it was then.

Field et al. (2016) included 22 species of Lycopodioideae in their analysis, which suggested the relationships among the genera shown in the following cladogram, where the number of species included in the study is shown in parentheses:[7] Lycopodiastrum (only sp.)