海姆达尔（Heimdallr，古北欧语：Heimdallr），是光之神、破晓之神。是北欧神话中一个比较神秘的神祇。他的另一个化名是里格（Ríg）。

在北欧两大神族群里，尚不能确定海姆达尔是属于阿萨神族还是华纳神族。一般认为其父亲为奥丁（Odin），但也有人认为和海洋有密切关系的海姆达尔，应属于掌管海、风等物的华纳神族。传说中，海姆达尔的母亲是九个姊妹，〈海姆达尔之神秘〉诗中提到：「我是九个母亲的孩子，也是九个姊妹的儿子」，诗中所指的这九个姊妹可能是海浪的化身。

海姆达尔是阿斯嘉特的守护者，为了肩负这样的任务，诸神让他拥有最好的眼睛，即使在黑夜中也可看到极远。给他非常灵敏的耳朵，连草木、羊毛生长的声音也可听到，而且日夜不休息也不会疲惫。他还拥有一个名为「加拉尔（Gjallarhorn）」的警告号角。海姆达尔平日就守在彩虹桥附近，用他过人的眼睛和耳朵监视着，不让巨人偷跑进神国领域。但他也有自己的宫殿「希敏约格」（Himinbjorg)，意即「天卫之宫」）。另外，他的马叫「古尔托普」（Gultopp，意即「金顶」）。 他最讨厌的人是邪神洛基（Loki），因此他也被称作「洛基的敌人」。在诸神的黄昏中，海姆达尔将会和洛基展开对决。同时，他也是最后倒下的神。

In Norse mythology, Heimdallr (modern Icelandic Heimdallur) is a god who possesses the resounding horn Gjallarhorn, owns the golden-maned horse Gulltoppr, has gold teeth, and is the son of Nine Mothers. Heimdallr is attested as possessing foreknowledge, keen eyesight and hearing, and is described as "the fairest of the Æsir" (perhaps a reference to his balanced nature), and keeps watch for the onset of Ragnarök while drinking fine mead in his dwelling Himinbjörg, located where the rainbow bridge Bifröst meets Asgard, the world of the gods. Heimdallr is said to be the originator of social classes among humanity and once regained Freyja's treasured possession Brísingamen while doing battle in the shape of a seal with Loki. Heimdallr and Loki are foretold to kill one another during the events of Ragnarök. Heimdallr is additionally referred to as Rig, Hallinskiði, Gullintanni, and Vindlér or Vindhlér.