The objective of this chapter is to review the existing literature on the genetic basis of human decision-making behavior. Identifying genetic influences has the potential to shed light on the underlying neurobiological mechanisms of decision-making, in that genes can convey information about which neurotransmitter and brain metabolism processes are relevant while making decisions. Most studies published to date have applied candidate gene approaches. In this type of study, researchers investigate the associations between distinct gene polymorphisms and certain aspects of decision-making behavior. However, since personality and behavior are the results of a complex interplay of different biological components, more recent research often considers multiple genes simultaneously, via haplotype analyses, gene–gene interaction studies, polygenetic risk scores or genome-wide analyses. A vast body of research has implicated genes related to dopaminergic, serotonergic, oxytocinergic and vasopressinergic neurotransmission in relation to decision-making, although the empirical evidence is often ambiguous. Therefore, studying interactions between biological and environmental factors, e.g., by means of epigenetics, might bridge the gap between ‘nature and nurture’ and might represent a starting point for future research approaches in the field.