Siphonalia pfefferi, common name Pfeffer's whelk, is a species of sea snail, a marine gastropod mollusc in the family Buccinidae, the true whelks.

Siphonalia pfefferi has a shell that reaches a length of 40–50 mm.

The shape of this shell is ovate, with several prominent ribs per whorl and a siphonal canal slightly recurved.

The surface has a white or cream-yellow background color, with small orange or pale brown spots.

This species is endemic to southern Japan, mainly in Kii Peninsula and southward.