Little research has addressed age-gap romantic relationships (romantic involvements characterized by substantial age differences between partners). Drawing on evolutionary and socio-cultural perspectives, the present study examined normative beliefs and commitment processes among heterosexual women involved in age-gap and age-concordant relationships. Results indicated that woman-older partners were the most satisfied with and committed to their relationships, relative to woman-younger and similarly aged partners, consistent with socio-cultural predictions. Additional analyses revealed that satisfaction, alternatives, investments, and normative beliefs accounted for differing degrees of variance in the prediction of commitment among age-gap and similarly aged partners, with greater explained variance among partners of similar ages. Thus, among female heterosexual age-gap partners, factors beyond traditional predictors of commitment may be important in understanding the maintenance of these relationships.