Below are lists of extant fern families and subfamilies using the classification scheme proposed by the Pteridophyte Phylogeny Group in 2016 (PPG I). The scheme is based on molecular phylogenetic studies, and also draws on earlier classifications, particularly those by Smith et al. (2006), Chase and Reveal (2009), and Christenhusz et al. (2011). It rejects the very broad circumscription of some families used by Christenhusz and Chase (2014), whose Aspleniaceae corresponds to the entire suborder Aspleniineae of PPG I.