鼬科，又名貂科（学名：Mustelidae）是哺乳动物下食肉目熊型总科中的一个科。鼬科包括水獭、獾、鼬、貂、黄鼠狼等动物。过去臭鼬科动物也被看作是鼬科的，但现在被另分一科了。

大多数鼬科动物身体细长、灵巧，只有獾亚科的动物和貂熊的身材比较臃肿。一般它们的皮毛呈棕色或黑色，有些有斑点、条纹等。尾和四肢比较短。足上有五根弯的、无法收入的爪。嘴比较短，耳小。牙齿数从28至38枚不等，一个共同特征是缺乏上颚第二枚臼齿。与臭鼬科动物一样所有鼬科动物拥有发达的肛腺，它们使用其分泌物来标志领域。有些种（比如蜜獾）也使用其肛腺来防卫自己。

The Mustelidae (from Latin mustela, weasel) are a family of carnivorous mammals, including the otter, badger, weasel, marten, ferret, mink and wolverine. Mustelids are diverse and the largest family in the order Carnivora. The internal classification is still disputed, with rival proposals containing between two and eight subfamilies. One study, published in 2008, questions the long-accepted Mustelinae subfamily, and suggests that Mustelidae consist of four major clades and three much smaller lineages.