Seguenzia stephanica is a species of extremely small deep water sea snail, a marine gastropod mollusk in the family Seguenziidae.

The white shell is elevated, trochiform, with a minute glassy smooth nucleus and about five subsequent whorls.

The axial sculpture consists of low thin sharp lamellae with wider interspaces, over riding the peripheral keel on the spire but not on the body whorl.

The axial sculpture consists of fine, even, arcuate wrinkles, which, except where they bead the posterior thread, are chiefly visible in the interspaces.

"[3] This species occurs in the Pacific Ocean from the Aleutian Islands, Alaska (175°E) to Peru (3° S) between depths of 750 m to 5100 m; also off La Jolla and San Diego, California.