The sea mink is a recently extinct species of mink that lived on the eastern coast of North America around the Gulf of Maine on the New England seaboard. It was most closely related to the American mink, with continuing debate about whether or not the sea mink should be considered a subspecies of the American mink or a species of its own. The main justification for a separate species designation is the size difference between the two minks, but other distinctions have been made, such as its redder fur. The only known remains are bone fragments unearthed in Native American shell middens. Its actual size is speculative, based largely on tooth remains.

Mink are dark-colored, semiaquatic, carnivorous mammals of the genera Neogale and Mustela and part of the family Mustelidae, which also includes weasels, otters, and ferrets. There are two extant species referred to as "mink": the American mink and the European mink. The extinct sea mink was related to the American mink but was much larger.