Subclass: Opisthobranchia
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Opisthobranchia |
Species Under: Subclass Opisthobranchia
Sub-structure
- Order: Anaspidea
- Family: Aplysiidae
- Order: Cephalaspidea
- Family: Aglajidae
- Family: Aplustridae
- Family: Bullidae
- Family: Bullinidae
- Family: Diaphanidae
- Family: Gastropteridae
- Family: Haminoeidae
- Family: Philinidae
- Order: Notaspidea
- Family: Pleurobranchidae
- Family: Tylodinidae
- Family: Umbraculidae
- Order: Nudibranchia
- Suborder: Aeolidina
- Family: Aeolidiidae
- Family: Babakinidae
- Family: Embletoniidae
- Family: Eubranchidae
- Family: Facelinidae
- Family: Flabellinidae
- Family: Glaucidae
- Family: Tergipedidae
- Suborder: Arminina
- Family: Arminidae
- Family: Charcotiidae
- Family: Dironidae
- Family: Madrellidae
- Family: Zephyrinidae
- Suborder: Dendronotina
- Family: Bornellidae
- Family: Dendronotidae
- Family: Dotidae
- Family: Hancockiidae
- Family: Lomanotidae
- Family: Marianinidae
- Family: Scyllaeidae
- Family: Tethydidae
- Family: Tritoniidae
- Suborder: Doridacea
- Family: Geitodorididae
- Family: Mandeliidae
- Suborder: Doridina
- Family: Actinocyclidae
- Family: Aegiridae
- Family: Akiodorididae
- Family: Aldisidae
- Family: Chromodorididae
- Family: Conualevidae
- Family: Corambidae
- Family: Dendrodorididae
- Family: Discodorididae
- Family: Dorididae
- Family: Goniodorididae
- Family: Gymnodorididae
- Family: Hexabranchidae
- Family: Okadaiidae
- Family: Onchidorididae
- Family: Phyllidiidae
- Family: Polyceridae
- Subfamily: Nembrothinae
- Subfamily: Polycerinae
- Subfamily: Triophinae
- Family: Vayssiereidae
- Suborder: Porostomata
- Family: Heterodorididae
- Order: Sacoglossa
- Family: Caliphyllidae
- Family: Costasiellidae
- Family: Elysiidae
- Family: Hermaeidae
- Family: Limapontiidae
- Family: Oxynoidae
- Family: Plakobranchidae
- Family: Polybranchiidae