This study examines how romantic relationship cognitions are associated with changes of condomless anal sex among emerging adult gay and bisexual men. The sample was drawn from four waves of a prospective cohort study (N = 598; M_age = 18.2). Results suggest that condomless anal sex increased over the emerging adulthood period. Romantic relationship fear was associated with increased receptive condomless anal sex. Perceptions of greater romantic relationship control increased the likelihood of having insertive and receptive condomless anal sex. Findings suggest that romantic relationship cognitions are important to consider when understanding longitudinal changes in condomless anal sex in this population.