IAU (disambiguation)

IAU may refer to:
 * Immersion gold plating (IAu), a surface finish process in PCB manufacturing
 * International Astronomical Union
 * International American University
 * International American University College of Medicine
 * International Association of Universities
 * International Association of Ultrarunners (IAU) is the governing body for ultra running
 * Islamic American University
 * Islamic Azad University
 * Italian Actors Union, former name of the Guild of Italian American Actors, United States
 * 5000 IAU, an asteroid
 * Is Anyone Up?
 * International Crossbow Shooting Union or International Armbrustschützen Union (IAU)
 * Interamerican University of Puerto Rico

Iau is:
 * The Iau language
 * An occasional spelling for Eiao