The (Cephalopoda) - class
(Orthoceratoidea) - subclass

(Dissidocerida)
- order

(Orthocerida)
- order

(Pseudorthocerida)
- order

(Ascocerida)
- order

(Lituitida)
- order
The Nautiloids (Nautiloidea) - subclass

(Pseudorthocerida)
- order

(Orthocerida)
- order

(Ascocerida)
- order
(Palcephalopoda) -

(Plectronocerida)
- order

(Ellesmerocerida)
- order

(Endocerida)
- order

(Actinocerida)
- order

(Discosorida)
- order

(Tarphycerida)
- order

(Oncocerida)
- order
The Nautilids
(Nautilida)
- order
(Neocephalopoda) -

(Bactritida)
- order
(Ammonoidea) - subclass

(Goniatitida)
- order

(Ceratitida)
- order

(Ammonitida)
- order
(Coleoidea) - subclass
(Belemnoidea) -

(Aulacocerida)
- order

(Phragmoteuthida)
- order

(Donovaniconida)
- order

(Belemnitida)
- order

(Hematitida)
- order
(Neocoleoidea) -

(Ostenoteuthidae)
- order
The Decopods (Decapodiformes) - supderorder

(Boletzkyida)
- order
The Cuttlefishes
(Sepiida)
- order
The Bobtail Squids
(Sepiolida)
- order

(Spirulida)
- order

(Myopsida)
- order

(Oegopsida)
- order
The Octopuses & related (Octopodiformes) - supderorder
The Octopuses
(Octopoda)
- order

(Vampyromorphida)
- order