Background: Adolescents with intellectual disabilities face heightened risks of sexual victimisation, making sexuality education a critical protective factor. Method: This qualitative study explored how mothers conceptualise, implement, and experience challenges in delivering sexuality education within Indonesia's conservative sociocultural context. In-depth interviews were conducted with 10 mothers of adolescents aged 10–17 years with intellectual disabilities. Thematic analysis identified six core themes: (i) understanding of sexuality education, (ii) mothers’ attitudes, (iii) educational practices, (iv) barriers, (v) mothers’ roles, and (vi) support needs. Results: Mothers primarily linked sexuality education to hygiene, body protection, and abuse prevention, usually taught reactively during puberty or behavioural incidents. Barriers included discomfort, low confidence, stigma, limited knowledge, and a lack of culturally appropriate resources. Despite these constraints, mothers recognised their central role and expressed strong motivation for structured training and collaboration. Conclusion: Findings highlight the urgency of family-centred, culturally sensitive interventions to promote safer, inclusive environments. © 2026 Australasian Society for Intellectual Disability, Inc.