Lex loci celebrationis is a Latin term for a legal principle in English common law, roughly translated as "the law of the land (lex loci) where the marriage was celebrated". It refers to the validity of the union, independent of the laws of marriage of the countries involved: where the two individuals have legal nationality or citizenship, or where they live (reside or are domiciled). The assumption under the common law is that such a marriage, when lawfully and validly celebrated under the relevant law of the land, is also lawful and valid.
In the main part of the United Kingdom being the jurisdiction of England, or England and Wales, as well as in many of the other legal jurisdictions largely or partly following the British tradition of jurisprudence in addition to their modified local versions of the English Common law, the legal principle behind this legal term was modified, qualified and further elaborated both by legal developments in the Common law (Lord Dunedin's Berthiaume v D'Astous case (HL 1930) (AC 79), in which Dunedin in the Appellate Committee of the House of Lords ruled that "If a marriage is good by the laws of the country where it is effected, it is good all the world over, no matter whether the proceedings or ceremony which constituted marriage according to the law of the place would not constitute marriage in the country of the domicile of one or other of the spouses. If the so-called marriage is no marriage in the place where it is celebrated, there is no marriage anywhere, although the ceremonial proceedings if conducted in the place of the parties’ domicile would be considered a good marriage"), as well as by codification by Statute (Foreign Marriage Act 1892, 55 & 56 Vict., Chapter 23). Under the English common law, whether a party needs to be present is treated as a formality of the marriage ceremony, so if a proxy marriage is valid by the law of the place where the marriage was celebrated then it will be recognised in England.