彩虹桥（Bifrost，Bifröst，古北欧语：Bilröst），意即「摇晃的天国道路」。在北欧神话中，是链接阿斯嘉特（Asgard）和米德加尔特（中庭/Midgard）的巨大彩虹桥。

阿萨神族（Aesir）的诸神每天都会沿着彩虹桥来到世界之树（Yggdrasil）旁的兀儿德之泉开会。海姆达尔（Heimdallr）是此桥的守护者，他在此监视巨人国，防止他们对阿斯嘉特（Asgard）的侵扰。海姆达尔的居所「希敏约格」（Himinbjorg）其大厅就位在桥的末端。

在诸神的黄昏中，彩虹桥将被史尔特尔（Surtur）等巨人践踏而崩塌。

In Norse mythology, Bifröst (/ˈbɪvrɒst/ or sometimes Bilröst or Bivrost) is a burning rainbow bridge that reaches between Midgard (the world) and Asgard, the realm of the gods. The bridge is attested as Bilröst in the Poetic Edda; compiled in the 13th century from earlier traditional sources, and as Bifröst in the Prose Edda; written in the 13th century by Snorri Sturluson, and in the poetry of skalds. Both the Poetic Edda and the Prose Edda alternately refer to the bridge as Ásbrú (Old Norse "Æsir's bridge").