Adolescence is a developmental period of significant change and increasing independence, during which parents and caregivers play a critical role guiding their teen toward adulthood. Parents of adolescents with disability face heightened challenges managing their teens’ growing independence and shift to adult-based services across health, recreation, and employment. Using a mixed-methods-treatment-group-only design, this study explored the implementation and outcomes of a program designed to build parenting capacity to support their adolescent with disability. Parents enrolled in one of ten groups were invited to attend three sessions covering content tailored to adolescent development including post-school opportunities, financial support, risk-taking and decision-making, future planning, relationships, and mental health. Surveys were administered pre-program, post-program, and six months after program participation (n = 160) to measure intervention outcomes including parenting self-efficacy, self-advocacy, adolescent self-advocacy, parent confidence to support their adolescent’s growing independence, confidence to support their adolescent through sensitive developmental stages, parental hopes and aspirations, and parental empowerment. A subset of parents (n = 11) also participated in semi-structured interviews about the program’s acceptability and usefulness, and their satisfaction with the program content and delivery. All outcome variables except parent hopes and aspirations increased significantly from pre- to post-program. Parent self-efficacy, self-advocacy, and parental empowerment remained higher 6 months after program completion. Thematic analysis identified program strengths as the co-facilitation model of program delivery, practical and actionable content, the use of narratives and the facilitator’s lived experience as parents of adolescents with disability, the use of visualizations (video, pictures, diagrams), and the service provider’s trusted reputation and credibility. In conclusion, an online co-facilitated group program for parents of adolescents with disability can contribute to positive change for families by improving parent confidence, self-advocacy, and parental empowerment.