Ian Donald Dietrich Eaves, MVO FSA, is a British researcher and consultant on arms and armour. He served as the Keeper of Armour at the Royal Armouries for eighteen years, from 1978 to 1996. Also starting in 1978, and continuing until 1983, he served as the editor of the Journal of the Arms & Armour Society; he was appointed the society's president in 1995, and currently serves as a vice-president emeritus. He has written and translated several articles for journals, including the society's.