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: IGY), NASA defunct solar-powered autonomous drone helicopter on Mars

See also

Iggy (disambiguation) IGI (disambiguation) IG (disambiguation) GY (disambiguation), for 1 Gy GM LGY engine