Eatoniella stewartiana is a species of marine gastropod mollusc in the family Eatoniellidae.

[3] The species closely resembles Eatoniella kerguelenensis subsp.

chiltoni, but can be differentiated by its smaller sizer, thinner, emi-transparent shell and false margined sutures.

[1] The holotype was collected in September 1962 by Elsie Smith on Ocean Beach, Stewart Island, near high tide on Bostrychia red algae.

[2] Fossil evidence has shown that Eatoniella stewartiana was very common on the coastal terraces near modern-day Kaikōura Peninsula during the Pleistocene era.