Sex/gender is a primary constituent of individual differences in human behavior. In this chapter, we examine the role of sex/gender in economic decision-making, focusing on behavioral, neurobiological, and hormonal factors that underpin value-based choices. We report that two core regions of the brain valuation system, the striatum (male > female) and the ventromedial prefrontal cortex (female > male), show opposing sex/gender differences in gray matter volume, but their relations to function remain underexplored. Applying a five-step decision-making framework (representation, valuation, action selection, outcome evaluation, and learning), we explore how sex/gender differences and sex hormones impact each stage. We discuss how these differences or their absence find their expression in individual characteristics such as risk attitude, time preferences, prosociality, behavioral flexibility, or learning ability. For example, testosterone increases both temporal and social discounting and reduces connectivity between the temporoparietal junction and the striatum in men. Similarly, estrogen increases temporal discounting in women. Finally, we discuss the gradual passage from a binary conceptualization to a continuous representation of sex/gender and make a series of recommendations for future neuroeconomic studies.