Plagiorchiida — буйны атрад смактуноў. Уваходзіць у склад падкласу дыгенетычныя смактуны (Digenea), самага вялікага па ліку відаў сярод усіх смактуноў.
Ніжэй пазначаны сямействы з размеркаваннем па надсямействах і падатрадах:
- Apocreadiata
- Apocreadioidea Skrjabin, 1942
- Bivesiculata
- Bucephalata
- Bucephaloidea Poche, 1907
- Echinostomata
- Echinostomatoidea Looss, 1902
- Caballerotrematidae Tkach, Kudlai & Kostadinova, 2016
- Calycodidae Dollfus, 1929
- Cyclocoelidae Stossich, 1902
- Echinochasmidae Odhner, 1910
- Echinostomatidae — Эхінастаматыды Looss, 1899
- Fasciolidae — Фасцыяліды Railliet, 1895
- Himasthlidae Odhner, 1910
- Philophthalmidae Looss, 1899
- Psilostomidae Looss, 1900
- Rhytidodidae Odhner, 1926
- Typhlocoelidae Harrah, 1922
- Gymnophallata
- Gymnophalloidea Odhner, 1905
- Haploporata
- Haploporoidea Nicoll, 1914
- Haplosplanchnata
- Haplosplanchnoidea Poche, 1925
- Hemiurata
- Azygioidea Lühe, 1909
- Hemiuroidea Looss, 1899
- Accacoeliidae Odhner, 1911
- Bathycotylidae Dollfus, 1932
- Bunocotylidae Dollfus, 1950
- Derogenidae Nicoll, 1910
- Dictysarcidae Skrjabin & Guschanskaja, 1955
- Didymozoidae Monticelli, 1888
- Gonocercidae Skrjabin & Guschanskaja, 1955
- Hemiuridae Looss, 1899
- Hirudinellidae Dollfus, 1932
- Isoparorchiidae Travassos, 1922
- Lecithasteridae Odhner, 1905
- Paraccacladiidae Bray & Gibson, 1977
- Ptychogonimidae Dollfus, 1937
- Sclerodistomidae Odhner, 1927
- Sclerodistomoididae Gibson & Bray, 1979
- Syncoeliidae Looss, 1899
- Heronimata
- Lepocreadiata
- Lepocreadioidea Odhner, 1905
- Monorchiata
- Monorchioidea Odhner, 1911
- Opisthorchiata
- Opisthorchioidea Braun, 1901
- Pronocephalata
- Paramphistomoidea Fischoeder, 1901
- Pronocephaloidea Looss, 1899
- Transversotremata
- Transversotrematoidea Witenberg, 1944
- Xiphidiata
- Brachycladioidea Odhner, 1905
- Gorgoderoidea Looss, 1901
- Microphalloidea Ward, 1901
- Diplangidae Yamaguti, 1971
- Exotidendriidae Mehra, 1935
- Faustulidae Poche, 1926
- Microphallidae Ward, 1901
- Pachypsolidae Yamaguti, 1958
- Phaneropsolidae Mehra, 1935
- Pleurogenidae Looss, 1899
- Prosthogonimidae — Прастаганіміды Lühe, 1909
- Renicolidae Dollfus, 1939
- Zoogonidae Odhner, 1902
- Opecoelioidea Ozaki, 1925
- Plagiorchioidea Lühe, 1901
- Auridistomidae Lühe, 1901
- Brachycoeliidae Looss, 1899
- Cephalogonimidae Looss, 1899
- Choanocotylidae Jue Sue & Platt, 1998
- Echinoporidae Krasnolobova & Timofeeva, 1965
- Encyclometridae Mehra, 1931
- Leptophallidae Dayal, 1938
- Macroderoididae McMullen, 1937
- Meristocotylidae Fischthal & Kuntz, 1981
- Ocadiatrematidae Fischthal & Kuntz, 1981
- Orientocreadiidae Yamaguti, 1958
- Plagiorchiidae Lühe, 1901
- Styphlotrematidae Baer, 1924
- Telorchiidae Looss, 1899
- Thrinascotrematidae Jue Sue & Platt, 1999
- Urotrematidae Poche, 1926
- Troglotremata