Introduction: The current study aimed to compare knowledge about and attitudes toward the sexuality of elderly people by gender and developmental periods. Materials and Method: A total of 206 young adults aged 18-27 years and 127 older adults aged 60-86 years participated in this study. "The Aging Sexuality Knowledge and Attitudes Scale" and Sociodemographic Information Form were applied to the participants. Descriptive statistics were presented to explore topics including active sexual life, the frequency of sexual intercourse, and how each group defined their sexuality. Results: The results of this study showed that 57.5% of the older adults continued to have an active sexual life. A two-way multivariate analysis of covariance indicated that the main effects of developmental period (p < .001) and gender (p .01) were statistically significant; however, the interaction effect of developmental period and gender was not statistically significant (p .05). The main effect of developmental period indicated that the young adults reported less knowledge about and a more permissive attitude toward elderly sexuality than the older adults did. The main effect of gender indicated that the females had less knowledge about elderly sexuality than the males. Conclusion: The results of this study provide important contributions to both educational interventions in developmental psychology, gerontology, and geriatric nursing and the theoretical literature by examining the knowledge and attitudes toward the sexuality of the elderly from a developmental perspective for the first time in Turkey.