Neptunea arthritica is a species of sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks.

[1] The length of the shell attains 75.4 mm.

This species occurs off Japan and as an alien species in the Black Sea.

N. arthritica contains toxic tetramethylammonium salts (referred to as "tetramine" in this context) in its tissues, especially the salivary gland, and has the potential to cause human poisoning.

This Buccinidae-related article is a stub.