Afrolittorina knysnaensis, common name the southern periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.

Its color varies from brown with a pattern of dots with a dark ring around its every whorl, to pure black.

The smooth shell has a conical shape with a short spire.

The aperture is subcircular and has a transparent, horny operculum.

This marine species occurs off Namibia to Southern KwaZuluNatal; in the Indian Ocean off Réunion.