"Iron John" is a German fairy tale found in the collections of the Brothers Grimm, tale number 136, about an iron-skinned wild man and a prince. The original German title is Eisenhans, a compound of Eisen "iron" and Hans. It represents Aarne–Thompson type 502, "The wild man as a helper".

Iron John: A Book About Men is a book by American poet Robert Bly, and an exegesis of Iron John, a parable belonging to the Grimms' Fairy Tales (1812) by German folklorists Brothers Grimm about a boy maturing into adulthood with help of the wild man.