IFN is an abbreviation for interferon, a signaling protein.
IFN or IfN may also refer to: Integrated Flux Nebula, a cloud of gas and dust illuminated by the integrated flux of all the stars in the Milky Way (rather than a single star or group of stars) Leibniz Institute for Neurobiology (Leibniz-Institut für Neurobiologie), Germany Isfahan International Airport (IATA code)