Recent research in the areas of neuroscience, neuroendocrinology, and genetics is reviewed providing convincing evidence for why and how the effects of bullying can last a lifetime. Specifically, the research reviewed herein indicates that (a) the brain experiences peer victimization in a similar way to physical pain, (b) peer victimization is robustly linked to dysregulation of the neuroendocrine response to stress, (c) certain genetic profiles place bullied children at greater risk for poorer sequelae, and (d) the experiences of peer victimization become biologically embedded in the physiology of the developing person, placing him or her at risk for life-long mental and physical health problems. These studies highlight the urgent need to prioritize the reduction of bullying.