韦德尔氏海豹（拉丁文学名：Leptonychotes weddellii），又名威德尔海豹、威氏海豹或威德尔氏海豹，是海豹科下韦德尔氏海豹属的唯一种动物，由一位英国的南极的航海探险家詹姆士·威德尔(James Weddell)所命名。这种海豹主要分布于南极周围、南极洲沿岸附近海域，据估计目前大约有80万头。体长约3公尺，雌性体形大于雄性，以鱼类、头足类等海洋中的生物为食。

相对于一般的海豹，由于韦德尔氏海豹较为温驯，而且牙齿没有食蟹海豹尖锐，这使捕食牠们的鲸类更为喜爱捕食。

The Weddell seal, Leptonychotes weddellii, is a relatively large and abundant true seal (family: Phocidae) with a circumpolar distribution surrounding Antarctica. Weddell seals have the most southerly distribution of any mammal, with a habitat that extends as far south as McMurdo Sound (at 77°S). It is the only species in the genus Leptonychotes, and the only member of the Antarctic tribe of lobodontine seals to prefer in-shore habitats on shore-fast ice over free-floating pack ice. Because of its abundance, relative accessibility, and ease of approach by humans, it is the best-studied of the Antarctic seals. An estimated 800,000 individuals remain today. Weddell seal pups leave their mothers at a few months of age. In those months, they are fed by their mothers' warming and fat-rich milk. They leave when they are ready to hunt and are fat enough to survive in the harsh weather.