ABSTRACT The present study examined how the similarity and complementarity of gender-related attitudes, behaviors, interests, and personality traits related to partner selection and relationship adjustment in the context of serious, romantic relationships. Results revealed the important role of gender-related attitudes in relationships, indicating that study participants tended to be paired with partners who held similar attitudes, and that couples who were similar in attitudes had higher dyadic adjustment. Furthermore, the nature of the couples' attitudes affected (a) the extent to which couples were paired on the basis of complementary interests and behaviors, and (b) the relation between partner's gender-related behaviors and dyadic adjustment. Results support previous research citing the importance of attitude similarity in interpersonal attraction, and demonstrate that these findings can be generalized to ongoing, close relationships.