LDN

LDN is a mobile phone abbreviation for London. It can also refer to:

* LDN, a London based professional wrestling promotion.
* London Daily News, the shortlived London newspaper owned by British newspaper tycoon Robert Maxwell
* BBC London, formerly known as BBC LDN
* LDN (song), a 2006 single by Lily Allen

;Other uses
* Low dose naltrexone, an "off-label" treatment for immunologically-related disorders
* Licensed Dietician/Nutritionist, a person licensed by a governing authority (such as one of the United States) who has met specific education and training curriculum requirements in order to distribute nutrition information for the prevention and/or treatment of specific disease states, and for the promotion of wellness
* Day-Night Average Sound Level (abbreviated Ldn or DNL), a measure of average noise level over a day
* LSB Developer Network, Linux Standard Base Developer Network, meant to serve as the central, community-based source of information for software developers writing portable Linux applications, much in the vein of MSDN
* Long Distance Network, a term from telecommunication