LDN may refer to:
Arts and media "LDN" (song), a 2006 single by Lily Allen London Daily News, former newspaper BBC London (formerly BBC LDN), broadcasting body
Language Láadan, a feminist, sci-fi conlang (ISO 639-3:ldn)
Medicine Low-dose naltrexone, to treat immune diseases Licensed dietitian nutritionist, a qualified dietician
Places Lamidanda Airport, Nepal (IATA code) Lanao del Norte, province in Northern Mindanao, Philippines London, in British contractional slang Llandanwg railway station, north Wales (GBR:LDN)
Science and technology Day-night average sound level (Ldn) Linked Data Notifications, a communications protocol Lynds' Catalogue of Dark Nebulae, in astronomy