Despite increasing awareness of the contributions of biological sciences in criminology, the extent to which biological variables are incorporated in criminological research and theories remains limited. This dissertation consists of five papers that examine biological factors in conjunction with social environmental and psychological variables to gain a more complete understanding of the etiology of antisocial behavior. Paper 1 examined whether a biological mechanism may help to explain why social environmental factors that are identified in many criminological theories are associated with antisocial behavior. The finding that low heart rate partly mediated the relationship between early social adversity and antisocial behavior in children gives rise to a social neurocriminology perspective whereby social environmental factors influence biology to in turn lead to crime. Paper 2 expanded on this empirical proof of concept by proposing a biopsychosocial model to demonstrate how autonomic arousal can be incorporated into extant criminological theories. Paper 3 employed a biological perspective to explain an important phenomenon in criminology regarding the higher rate of male crime. Using longitudinal mediation analysis, the study is the first to document that lower heart rates in males at age 11 years partly explain their higher levels of offending in adulthood. Findings support the consideration of biological processes in theoretical accounts of the gender gap. Paper 4 examined whether a nutritional factor, vitamin D, confers resilience to childhood antisocial behavior. The finding that meeting vitamin D sufficiency (serum 25-hydroxyvitamin D concentration ≥ 30 ng/mL) nullified the social adversity-antisocial behavior relationship documents for the first time, a protective effect of vitamin D on antisocial behavior. Paper 5 examined the neural mechanisms underlying antisocial behavior using transcranial direct current stimulation. A double-blind, placebo-controlled, stratified, randomized trial on healthy adults provided the first experimental evidence that increasing activity in the prefrontal cortex can reduce intentions to commit aggression. This effect was account for, in part, by enhanced perceptions of moral wrongfulness regarding the aggressive acts. Together, these studies have the potential to advance the field of criminology at conceptual and theoretical levels, as well as knowledge on the development of prevention and intervention programs for such behavior.