See text Grammitidoideae is a subfamily of the fern family Polypodiaceae, whose members are informally known as grammitids.

[2] This group was previously treated as a separate family, Grammitidaceae until molecular phylogenies showed it to be nested within the Polypodiaceae.

In 2011, Christenhusz et al.[3] placed the grammitid ferns in the subfamily Polypodioideae, within the Polypodiaceae, as an informal group without rank.

In 2014, Christenhusz and Chase expanded the circumscription of both family and subfamily, placing the Polypodioideae as previously delimited, including grammitids, in tribe Polypodieae.

The PPG I classification of 2016 largely reverted to the 2011 circumscriptions of these groups, but placed the grammitids in a new subfamily.