FJJ can refer to:
Flatbush Jewish Journal, an Orthodox Jewish weekly newspaper based in Brooklyn, New York, U.S. Fondation Jean-Jaurès, a French socialist think tank FJJ, a British military squadron that was part of the No. 28 Elementary Flying Training School RAF, by squadron code; see List of RAF squadron codes
See also
Frans Julius Johan van Eysinga (1818–1901) or F. J. J. van Eysinga, a Dutch politician