IGY

IGY may refer to:


 * Immunoglobulin Y (IgY), a type of antibody found in birds but not mammals
 * International Geophysical Year (I. G. Y.)
 * "I.G.Y. (What a Beautiful World)", a 1982 song by Donald Fagen
 * Israel Gay Youth
 * Ingenuity (helicopter) (ICAO operator code: ), NASA defunct solar-powered autonomous drone helicopter on Mars