Background: Parents experience difficulties supporting children with intellectual disabilities when they exit the school system. One promising way to mitigate this problem is to set up school-based parent support groups. This study aimed to examine the development and feasibility of school-based parent support groups in South Korea designed to connect parents of transition-aged youth with intellectual disabilities. Methods: This qualitative study included 29 participants. Five focus groups and seven individual interviews were conducted with parents as co-researchers. Data were analysed using thematic analysis. Results: Participants reported meaningful experiences after participating in the parent support groups. However, it is critical to consider the following components to promote their feasibility: clearly defined roles, small group meetings, school-based initiatives, and collaboration. Conclusions: Parent support groups could be a valuable way to promote parental empowerment. Implications for future practices are suggested.