This study used a theoretical framework derived from evolutionary biology and animal research to investigate dominance in heterosexual couples of young adults. We operationalized dominance as decision-making power and hypothesized that there would be agreement within couples as to who is dominant and who is subordinate, and that dominance would be consistent across different contexts. We also investigated variation in the sex of the dominant individual and in the strength of dominance across couples. Study participants were 140 young men and women (including 19 heterosexual couples in which both partners were tested), most of whom were college students. Overall couple dominance and dominance strength were assessed with a single-item self-report questionnaire. An additional 40-item questionnaire was used to investigate dominance and amount of arguing in different aspects of romantic relationships. Among the 19 couples, there was a significant agreement in the assessment of dominance between partners. Furthermore, among all study participants, assessments of couple dominance were consistent with perceived asymmetries in decision-making with regard to joint leisure activities, couple intimacy, and division of roles. Couples without clear dominance (egalitarian) generally argued less often than couples with strong or weak dominance. Men were more likely to be dominant than women. Overall, the principles underlying dominance in human heterosexual couples appear to be similar to those operating in nonhuman primates. Evolutionary and comparative theories of dominance could provide a valid framework for future studies of human couple dominance, in which both physiological and fitness correlates of dominance and subordination could be investigated.