The purpose of this study was to support the development of mathematics and self-determination skills of young adults with extensive support needs. Mathematical problem solving is a natural context for teaching two component skills of self-determination: self-monitoring and goal setting. Three young adults with extensive support needs (i.e., autism and intellectual disability) were taught to solve real-world thematic word problems using modified schema-based instruction (MSBI). To build self-determination skills, participants self-monitored completion of problem-solving steps using a task analysis, self-graphed steps completed independently correct and then set goals for subsequent sessions. Generalization was measured within the context of scaling ingredients from a recipe without instructional supports of a task analysis or graphic organizer. Results of the multiple probe across participants design indicate a functional relation between MSBI and steps of problem solving completed independently correct. Implications for practice and research are discussed.