A language-based social skills instruction intervention used to prepare middle and high school students with emotional/behavioral disorders for return to less restrictive public school placements was evaluated. The daily 50-minute intervention focused on repetitive readings, recitations, and role-playing of skill step procedures until students achieved mastery on each required task in five broad dimensions: peer relations, self-management, academic, compliance, and assertion. The students were divided into three groups according to the length of intervention (under 2 years, 2 to 3 years, and more than 3 years). Dependent t tests were used to test the effects of prolonged intervention on past year and final year disruptive behavior totals and response to a self-control question for students in each group. In addition, a chi-square was used to evaluate the frequency of students with four or fewer disruptive behaviors across groups to determine progress toward unsupervised transition. Implications for social skills intervention and communication disorders practice are discussed.