This study examines differential stability in attitudes toward homosexuality using panel data representative of the American adult population. While attitudes toward homosexuality have shifted considerably on the aggregate-level over the past few decades, this study shows that such attitudes are remarkably stable on the individual-level. Employing conditional change models, this study also provides a test of the aging-stability hypothesis with regard to attitudes toward homosexuality. That hypothesis is confirmed, as attitude stability is found to gradually increase with age. However, no other socio-demographic variables are found to have a consistent relationship with stability. The finding of an age-graded increase in stability suggests that attitudes toward homosexuality are formed predominantly early in life and that susceptibility to attitude change declines across the adult lifespan. This finding also supports a generational replacement explanation of recent changes in American public opinion on homosexuality as aging-stability translates into cohort effects on the aggregate-level.