This study examined the differential impact of implementing the "Self-Determined Learning Model of Instruction" (SDLMI) alone with implementing the SDLMI combined with "Whose Future Is It?" with transition aged students with intellectual disability in a cluster randomized trial in the state of Rhode Island. The state of Rhode Island is implementing systemic change in transition services and supports under the auspices of a Consent Decree entered into by the state with the U.S. Department of Justice. One area of focus is promoting self-determination during transition planning in the school context as a means to affect employment trajectories. This study focused on the impact of self-determination instruction on self-determination outcomes while youth were still in school, given research establishing a relationship between self-determination and employment outcomes. Latent mediation models suggested that students in the SDLMI-only group reported significant increases in their self-determination scores from baseline to the end of the year, and teachers of students in the SDLMI-only group saw students' goal attainment as predicting change in self-determination over the course of the year. Teachers reported significant changes in student self-determination in the SDLMI + "Whose Future Is It?" group. Implications for individualizing interventions to teach skills associated with self-determination in the context of planning and setting goals for the transition to integrated employment are discussed. [For the corresponding grantee submission, see ED585934.]