Romantic relationships are one of the most invested relationships; therefore, it is important to explore how various factors influence experiences in romantic relationships. Of interest are the possible mechanisms behind the well-established link between romantic attachment and self-esteem. Due to their common origin in early interpersonal experience, it was hypothesized that romantic relationship functions (i.e., motivations for engaging in relationships) and contingencies of self-worth (CSW; i.e., domains in which self-esteem is based) would be related and act as mediators in the attachment-self-esteem association. Participants were 49 undergraduate students from the University of Utah and their romantic partners (N = 98), age 18 to 44 ( M = 23.2). Eligible couples were required to have been in their current romantic relationship for at least three months; however, the average length of relationship was 21.6 months. Participants completed online surveys. Two sets of analytic procedures were performed. First, a confirmatory factor analysis was performed to see whether relationship functions and CSW were related. It yielded a three-factor model indicating they were separate constructs. Second, an actor-partner interdependence model (APIM) was tested to determine whether the relationship functions/CSW factor(s) would mediate the relationship between attachment (anxiety and avoidance) and self-esteem for men and for women interdependently. The APIM yielded various direct and indirect actor effects for women and men, respectively. None of the results found were identical across gender. Attachment anxiety and avoidance significantly predicted self-esteem for men (positive association) and women (negative association). Similarly, women’s attachment avoidance negatively predicted their own relationship functions, while men’s avoidance positively predicted their own relationship functions, which in turn negatively predicted their self-esteem (men only). Conversely, women’s attachment anxiety predicted their external CSW while men’s attachment avoidance predicted their internal CSW. Partner effects were also identified. Men’s attachment anxiety predicted women’s external CSW and self-esteem, while women’s external CSW predicted men’s self-esteem. Men and women function differently with regards to personal evaluations and relationship dynamics within the context of a romantic relationship. Further research should be conducted using a larger, more diverse, longitudinal sample in order to validate and extend the results of the current study.