Given the increased longevity of people with intellectual and developmental disabilities (IDD), future planning programs are becoming increasingly common. However, although siblings are likely to fulfill caregiving roles for people with IDD, siblings have not been included in future planning interventions. The purpose of this study was to evaluate the outcomes and feasibility of the Sibling Training for Early future Planning (STEP) program. Using quantitative and qualitative data, 18 siblings of individuals with IDD participated in the study. After completing the STEP program, participants demonstrated significantly improved feelings of empowerment, disability connectedness, family communication, and knowledge of adult disability services. The STEP program was also feasible given high attendance, low attrition rates, and high participant satisfaction. Implications for research and practice are discussed.