西格恩（Sigyn）是北欧神话中是邪神洛基（Loki）的第三任妻子。神话中几乎没提到关于她的故事，只提到她和洛基的生下了两个孩子：纳尔弗（Narve）和瓦利（Vali），后者和奥丁的孩子瓦利同名，但并非同一个人。

另一个提到西格恩的地方是，当巴德尔（Baldur）死亡之后，愤怒的诸神抓住罪魁祸首的洛基，用纳尔弗的肠子做为链锁，将他绑在一个巨岩之下，岩石上有丝卡蒂（Skadi）安放的毒蛇，让蛇毒滴落在他脸上。西格恩对洛基于心不忍，因此拿着水盆跟在旁边好接住滴下来的蛇毒。当水盆满时，西格恩只好拿开去倒掉，蛇毒又滴落在洛基脸上，疼痛难当的洛基因受不了而不住扭动，据说这时候世界就会跟着晃动，也就是地震。

In Norse mythology, Sigyn (Old Norse "victorious girl-friend") is a goddess and is the wife of Loki. Sigyn is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources, and the Prose Edda, written in the 13th century by Snorri Sturluson. In the Poetic Edda, little information is provided about Sigyn other than her role in assisting Loki during his captivity. In the Prose Edda, her role in helping her husband through his time spent in bondage is stated again, she appears in various kennings, and her status as a goddess is mentioned twice. Sigyn may appear on the Gosforth Cross and has been the subject of an amount of theory and cultural references.