Euomphaloidea, originally Euomphalacea, is an extinct superfamily of marine molluscs that lived from the Early Ordovician to the Late Cretaceous, included in the Gastropoda[1][3] but speculated as instead perhaps Monoplacophora.

[4] Euomphaloid shells are mostly discoidal and may be either orthostrophic (coils wrapped around an erect cone) or hyperstrophic (coils wrapped around an inverted cone); are widely umbilicate and commonly have a channel, presumed exhalent, within the angulation in the outer part of the upper whorl surface.

[5] As with almost all fossils, the taxonomic relations of and within the euophaloids can only be inferred from their remaining hard parts, in their case the shell.

The general inclusion of the Euomphalacea, as originally spelled[3][5] is based on the asymmetrically coiled tubular shell, suggestive if not indicative of the diagnostic torsion.

In the meantime Boucet and Rocroi (2005)Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) classified the Eumphaloidea simply as Paleozoic molluscs with anisostrophically coiled shells of uncertain position that are possibly gastropods, recognizing only five families, the: Prior to being included in the Euomphaloidea, the Anomphalidae, Elasmonematidae, Holopeidae, and Microdomatidae were included in the suborder Trochina, Cox & Knight 1960; the Anomphalidae in the Anomphalacea, the Elasmonematidae and Microdomatidae in the Microdomatacea, and the Holopeidae in the Plytyceratacea.