We review the role of emotion regulation in borderline personality disorder (BPD). We briefly discuss the historical development of BPD as a disorder where emotional regulation plays a key role. We review the concept of emotion regulation in general and explore both one-factor and two-factor models of emotion regulation. We discuss cognitive and attentional aspects of emotion regulation, and explore these regulatory controls as operating as both voluntary as well as automatic processes. We then turn to other neurophysiological models of emotion regulation in general and examine how those models, both neurophysiologically and neuroanatomically, are expressed in individuals with BPD. We examine how neuroimaging, both anatomical and functional, reveals the roles that various neuroanatomical structures play in the regulation of emotion in BPD. We conclude by creating a neurodevelopmental model that describes how a complex matrix involving the interplay of constitutional/biological predispositions with environmental stressors as well as with parental effectiveness in response to the child's emotion expression can impact key aspects of adult cognitive, affective, interpersonal, and behavioral functioning that culminate in a diagnosis of BPD.