Terebralia palustris, commonly known as the giant mangrove whelk, is a species of brackish-water snail, a mollusk in the family Potamididae.

[1] This tropical species which inhabits mangrove environments of the Indo-West Pacific region,[2] has the widest geographic distribution amongst the potamidids [3] extending from eastern Africa to northern Australia.

Terebralia palustris is the largest mangrove gastropod, with a maximum shell length of 190 mm recorded from Arnhem Land, Australia.

[2] Its Western Pacific distribution extends south from the Ryukyus to the Philippines and across Borneo, New Guinea and tropical Australia.

Terebralia palustris also occurs along the tropical and subtropical East African coastline including Kenya, Tanzania and Mozambique.