This chapter defines and characterizes emotion regulation in the context of normative human development. It reviews some of the literature on childhood maltreatment to illuminate critical components of emotion regulation as they are affected by early traumatic exposure. The chapter describes a developmentally informed evidence-based treatment for post-traumatic stress disorder (PTSD) related to childhood abuse in which both the interventions and the principles on which they are based emphasize the centrality of emotion regulation in recovery from trauma. Childhood maltreatment disturbs emotional processes in multiple ways. PTSD is an emotional disorder of particular interest because it involves contextually inappropriate over and under expressions of emotion. The ultimate recovery from a childhood marked by abuse, neglect and the perversion of meaning so often found in these situations must be a person's ability to join their communities as a loving, working and generative human being.