FNM can mean one of many things:
- Fábrica Nacional de Motores, a Brazilian automobile manufacturer
- Faith No More, an American alternative metal band
- Fannie Mae, U.S. mortgage guarantor, whose NYSE stock ticker symbol was FNM until its delisting
- Ferrocarriles Nacionales de México, Mexico's national railway company
- Ferrovie Nord Milano, an Italian transport company
- Free National Movement, a Bahamian political party
- Friday Night Magic, a Magic: The Gathering tournament