Prima Nocta also called Droit du seigneur (/ˈdrɑː də seɪˈnjɜːr/; French pronunciation: ​[dʁwa dy sɛɲœʁ]) ("lord's right"), also known as ius primae noctis (/ʒʌs ˈpraɪmiː ˈnɒktᵻs/; Latin pronunciation: [ju:s ˈpri:mae̯ 'nɔktɪs]) ("right of the first night"), refers to a supposed legal right in medieval Europe, and elsewhere, allowing feudal lords to have sexual relations with subordinate women (the "wedding night" detail is specific to some variants). There is no evidence of the right being exercised in medieval Europe, and all known references to it are from later time periods.

In 1527, Scottish historian Hector Boece wrote that the right had existed in Scotland until abolished by Malcolm III.[6] William Blackstone mentioned the custom in his Commentaries on the Laws of England (1765-1769), echoing Boece's claim.