Two prospective longitudinal studies of nationally representative samples of students with disabilities—the Special Education Elementary Longitudinal Study and the National Longitudinal Transition Study–2—are used to provide a broad look at the participation of parents of 11- through 19-year-old students with disabilities in Individualized Education Plan/transition planning meetings and their satisfaction with their involvement in them. Students’ attendance and the roles played in their transition planning meetings are also examined. Logistic regression analyses identify disability characteristics; demographics; aspects of parents’ involvement, expectations, and perceptions; experiences in students’ educational histories; and features of their instructional programs that help explain variations in parent and student participation, parent satisfaction, and student roles.