After Whittington, Chang, Dean, Fortey, Jell, Laurie, Palmer, Repina, Rushton & Shergold, 1997, and Gon III, 2002

<==o †Trilobita Walch, 1771 [nom. correct. ex Trilobiten Walch, 1771] (trilobites; trilobiitit)
   |?- †“Agnostida” Salter, 1864: †Eodiscina Kobayashi, 1939
   `--+--o †Redlichiida Richter, 1932
      |  |?-o †Dipharus Clark, 1923a [Pseudodipharus Korobov, 1980]
      |  |  |-- †D. insperatus Clark, 1923a
      |  |  `-- †D. privus (Korobov, 1980) [Pseudodipharus privus Korobov, 1980]
      |  |-- †Olenellina Walcott, 1890b [nom. correct. et transl. Palmer & Repina, 1993 pro Olenellidiae Walcott, 1890b] [taxonomic history]
      |  `-- †Redlichiina Richter, 1932
      |-- †Corynexochida Kobayashi, 1935
      |-- †Phacopida Salter, 1864
      |-- †Lichida Moore, 1959
      `--o †Librostoma Fortey, 1990
         |-- †Proetida Fortey & Owens, 1975
         |-- †Harpetida [Harpoidea]
         |-- †Ptychopariida Swinnerton, 1915
         `-- †Asaphida

Trilobita incertae sedis:

    †Missisquoiidae [?Leiostegiina:]
    †Isocolidae [?Asaphida:]
    †Granulariidae
    †Sarkiidae
    †Otarionidae
    †Plethopeltidae
    †Monorakidae
    †Bathynotidae [?Bathynotina]
    †Hicksiidae [?Redlichiina: Paradoxidoidea:]
    †Endymioniidae [?Asaphida:]
    †Hypermecaspididae [?Olenacea:]
    †Avoninidae [?Solenopleuracea:]
    †Catillicephalidae [?Solenopleuracea:]
    †?Yunnanocephalidae
    †Tricrepicephalidae [?Crepicephalacea]
    †Andrarinidae [?Dikelocephalacae:]
    †Burlingiidae [?Burlingiacea]
    †Raymondinidae [?Raymondinacea]

Reference(s):