Psilotopsida is a class of ferns or fern-like plants, considered to be one of the three classes of eusporangiate ferns. It should not be confused with the obsolete class Psilophytopsida. As circumscribed by Smith et al., 2006, Psilotopsida contains two families, Psilotaceae and Ophioglossaceae, placed in orders Psilotales and Ophioglossales, respectively.