Although research shows that spouses influence each other’s health behaviors and psychological well being, we know little about whether these patterns extend to young people in nonmarital as well as marital relationships. We use the National Longitudinal Study of Adolescent to Adult Health to consider how a romantic partner’s binge drinking and depression influence the respondent’s binge drinking and depression within 1,111 young adult couples and explore whether these processes are moderated by gender. We find that partners’ binge drinking is associated with increased odds of binge drinking for respondents and partners’ depression is associated with increased odds of depression for respondents. Further, depression among men is associated with reduced odds of binge drinking among their female partners. Findings suggest that processes of partner influence begin even in young adulthood with implications for cumulative effects on lifelong health behaviors and mental health.