This study used the standard setting to establish cutscores for the fidelity of implementation of an evidence‐based intervention, the Self‐Determined Learning Model of Instruction (SDLMI) designed to enhance goal‐directed actions in secondary students with and without disabilities. Cutscores were then applied to fidelity data from a large, randomized trial of the SDLMI with teacher implementers. Findings suggest teachers demonstrate a range of fidelity outcomes over time across three dimensions adherence, quality of delivery, and student responsiveness. Almost all teachers (93%) immediately meet cutscores for the adherence dimension after training, but smaller numbers meet cutscores for quality of delivery (64%) and student responsiveness (69%). However, the quality of delivery and student responsiveness showed growth over time with implementation experience and there was a small effect of intensifying implementation support. Practitioner points: The Self‐Determined Learning Model of Instruction (SDLMI) is implemented by teachers to support students in setting goals and implementing action plans, problem‐solving, and self‐regulating their learning as they revise their goals and action plans.It is important to understand how teachers implement the SDLMI in inclusive classrooms.Teachers can implement the SDLMI with their students, and their quality of delivery and student responsiveness to the SDLMI grows over time as teachers get coaching and implementation support. [ABSTRACT FROM AUTHOR]