Prior research has suggested that loneliness is associated with an implicit hypervigilance to social threats—an assumption in line with the evolutionary model of loneliness that indicates feeling socially isolated (or on the social perimeter) leads to increased attention and surveillance of the social world and an unwitting focus on self-preservation. Little is known, however, about the temporal dynamics for social threat (vs. nonsocial threat) in the lonely brains. We used high-density electrical neuroimaging and a behavioral task including social and nonsocial threat (and neutral) pictures to investigate the brain dynamics of implicit processing for social threat vs. nonsocial threat stimuli in lonely participants (N = 10), compared to nonlonely individuals (N = 9). The present study provides evidence that social threat images are differentiated from nonsocial threat stimuli more quickly in the lonely ( 116 ms after stimulus onset) than nonlonely ( 252 ms after stimulus onset) brains. That speed of threat processing in lonely individuals is in accord with the evolutionary model of loneliness. Brain source estimates expanded these results by suggesting that lonely (but not nonlonely) individuals showed early recruitment of brain areas involved in attention and self-representation.