This study addresses the critical, yet often neglected, area of parental sexual education for children with autism spectrum disorder (ASD), recognizing its vital role in healthy development and safety. An empirical study conducted in Israel investigated the characteristics of 42 mothers and 31 fathers of children with ASD and their communication about sexuality. It is hypothesized that mothers provide more comprehensive sexual education than fathers, particularly for daughters, and that higher parental knowledge of sexuality and ASD would predict broader education. Results indicate that mothers provide significantly more comprehensive sexual education across most topics, including privacy, sexual abuse prevention, and sexual maturation, compared to fathers. Mothers also discussed more sexual maturation topics with daughters than with sons. Crucially, mothers’ knowledge about sexuality significantly predicted the extent of their sexual education on topics like privacy, relationships, and general sexuality. However, fathers’ knowledge, whether of sexuality or ASD, did not predict their sexual education efforts. Knowledge about ASD did not predict sex education for either parent. These findings highlight the central and distinct role of mothers in sexual education for children with ASD and emphasize the need for tailored interventions to promote the sexual health and safety of this vulnerable population.