Background: Child sexual abuse (CSA) is a public health problem, and parents, especially mothers, play an important role in prevention by providing sexual and reproductive health education. However, local qualitative evidence on why parents’ knowledge does not always translate into practice remains limited. Objective: This study explored mothers’ experiences, barriers, and needs in providing sexual and reproductive health education to prevent CSA. Methods: This qualitative study was conducted in February 2023 at a public elementary school in Samarinda, East Kalimantan. Eleven mothers of lower-grade students were recruited through purposive sampling and took part in two focus group discussions. The discussions were audio-recorded, transcribed verbatim, and analyzed thematically. Results: Five themes emerged: (1) mothers’ efforts to prevent CSA, (2) shifting perspectives and responsibility for the education, (3) the content taught, (4) barriers, and (5) needs and recommendations. Mothers supervised their children’s mobility, limited physical contact with relatives, applied religion-based parenting, and taught body safety, privacy, and hygiene. Some mothers viewed the education less as taboo and more as a way to protect children. They regarded the education as the responsibility of parents and caregivers, although mothers often carried a larger share. Mothers faced barriers in communication and limited knowledge of age-appropriate content. They asked for health education for parents and teachers and preferred a printed booklet. Suggestions: This study suggests that parents build open, non-judgmental communication with their children, that comprehensive sexuality education be integrated into the school curriculum, and that families, schools, and health professionals strengthen their collaboration to support effective CSA prevention.