Demoulia is a genus of sea snails, marine gastropod mollusks in the family Nassariidae, the Nassa mud snails or dog whelks.

[1] The ovate-globose shell is covered with a downy epidermis.

The spire is short, conical with a papillary apex.

The outer lip is contracted, thickened externally and plicated internally.

[2] Species within the genus Demoulia include: