Many men physically, sexually, economically, and psychologically abuse women because of the interplay of personality characteristics and the teachings of the society in which they live. However, nearly 40 years of international research shows that one of the most powerful determinants of face-to-face and technology-facilitated violence against women is male peer support, which is the attachments to male peers and the resources that these men provide each other that perpetuate and legitimate woman abuse. Male peer support theory argues that when some men seek the advice of their male friends, they are given both encouragement and advice on how to abuse women who resist their perceived patriarchal authority or who do not provide sex on demand. There are now 11 variants of male peer support theory and the main objective of this chapter is to chronicle how this perspective was created and expanded to remain a vitally alive theory.