There is a need for a measure that examines teacher roles in implementing the Self-Determined Learning Model of Instruction (SDLMI) to advance equity in opportunities and experiences to build self-determination for all students, including students with disabilities and students of color with disabilities. In this study, the authors introduce a measure, the SDLMI teacher roles self-report measure, developed using the theoretical framework of the causal agency theory and knowledge of SDLMI implementation. This measure focuses on three roles defined in SDLMI implementation: advocate, facilitator, and instructor. Teachers are trained to take on each of these roles when implementing the SDLMI to provide inclusive and culturally responsive opportunities to promote self-determination. Preliminary findings from this study indicate that the advocate, facilitator, and instructor roles are positively correlated, but they are different constructs and demonstrate different patterns of relations with each other. Given these preliminary findings, more work is warranted to examine the relationship between the SDLMI teacher roles self-report measure and teacher implementation and student outcomes.