Sexual interest and capacity can extend far into later life and result in many positive health outcomes. Yet there is little support for sexual expression in later life, particularly among young adults. This study assessed and compared young adults’ explicit and implicit attitudes towards older adult sexuality. A sample of 120 participants (18–24 years; 58% female) completed a self-report (explicit) measure and a series of Implicit Association Tests capturing attitudes towards sexuality among older adults. Despite reporting positive explicit attitudes, young people revealed an implicit bias against the sexual lives of older adults. In particular, young adults demonstrated implicit biases favouring general, as compared to sexual, activities and young adults as compared to older adults. Moreover, the bias favouring general activities was amplified with regard to older adults as compared to younger adults. Our findings challenge the validity of research relying on self-reports of attitudes about older adult sexuality.