Evidence-based interventions such as the Self-Determined Learning Model of Instruction (SDLMI) promote abilities, skills, and attitudes associated with self-determination for secondary students with and without disabilities. Exploring factors that impact fidelity of implementation and lead to enhanced student outcomes will inform a greater understanding of the relationship between fidelity practices and teacher success in implementing the SDLMI. This systematic literature review summarizes how 12 empirical studies investigating the impact of the SDLMI on student outcomes describe fidelity procedures, measures, and outcomes in existing SDLMI research. Results summarize how fidelity of implementation was assessed, including characteristics of participants (i.e., implementors and students), the training implementers received, and specific fidelity data collection details and outcomes. There remains a need for improved reporting of detailed demographic information of participants (e.g., students and implementors), training dosage and ongoing support (e.g., coaching), and fidelity tools used. Implications for practice and research are discussed.