This monograph aims to provide information on the taxonomic status of all genera associated with the tetraphyllidean family Phyllobothriidae. Full treatments of the three valid species of the type genus, Phyllobothrium, in addition to the 47 valid species of Clistobothrium, Crossobothrium, Marsupiobothrium, Monorygma, Nandocestus, Orectolobicestus, Orygmatobothrium, Paraorygmatobothrium, Ruhnkecestus, and Scyphophyllidium are provided, as is a taxonomic history of the family. Of the valid genera historically associated with the family, only Phyllobothrium is considered to be an unambiguous member of the family. The genera Bibursibothrium, Calyptrobothrium, Cardiobothrium, Clistobothrium, Crossobothrium, Doliobothrium, Flexibothrium, Marsupiobothrium, Monorygma, Nandocestus, Orectolobicestus, Orygmatobothrium, Paraorygmatobothrium, Ruhnkecestus, Scyphophyllidium, and Thysanocephalum are valid, but are considered provisional members of the family. The taxonomic status of the remaining genera was also addressed. Aocobothrium, Dittocephalus, Hoaleshwaria, Phanobothrium, and Shindeobothrium are considered nomina dubia. Phyllobothrideum has been determined to be a nomen ad interim. Bilocularia, Biporophyllaeus, Cyatocotyle, Kowsalyabothrium, Maccallumiella, Mastacembellophyllaeus, Pillersium, Pithophorus, and Polipobothrium are considered genera inquirendae. Anindobothrium, Anthobothrium, Carpobothrium, Caulobothrium, Caulopatera, Ceratobothrium, Dinobothrium, Gastrolecithus, Guidus, Mixophyllobothrium, Myzocephalus, Myzophyllobothrium, Pelichnibothrium, Rhoptrobothrium, Trilocularia, and Zyxibothrium are considered valid, but incertae sedis with respect to their familial placements. Anthocephalum, Echeneibothrium, Rhabdotobothrium, Rhinebothrium, Rhinebothroides, Rhodobothrium, Scalithrium, and Spongiobothrium are valid members of the Rhinebothriidea