FDN may refer to:

Organizations
 Dolphin Air, a defunct Ermirati airline
 Flying Doctors Nigeria, an air ambulance service
 French Data Network, a French non-profit Internet service provider
 Fruta del Norte mine, an Ecuadorian gold mine

Politics
 National Democratic Front (Mexico) (Spanish: ), a defunct political coalition
 National Democratic Front (Peru) (Spanish: ), a defunct political party
 New Democratic Forces (French: ), a defunct political party in the Republic of the Congo
 Nicaraguan Democratic Force (Spanish: ), a Nicaraguan Contra group
 Nigerien Democratic Front (French: ), a defunct political party of Niger

Other uses
 Fairbanks Daily News-Miner, a newspaper in Fairbanks, Alaska, US
 Faridabad New Town railway station, in Haryana, India
 Fixed Dialing Number, in telephony