This study evaluated an intervention developed through an Institute of Education Sciences-funded Goal 2 research project to teach students with moderate intellectual disability (moderate ID) to solve addition and subtraction word problems. The intervention involved modified schema-based instruction that embedded effective practices (e.g., pictorial task analysis, graphic organizers, systematic prompting with feedback) for teaching mathematics skills to students with moderate ID. The dependent variables included steps performed correctly on a problem solving task analysis, number of problems solved, problem type discrimination, and generalization of problem solving skills. Results of a multiple probe across student dyads design indicated a functional relation between three dependent variables and the intervention. Upon completion of the intervention, all eight participants with moderate ID correctly followed the task analysis, discriminated problem types, and solved word problems. Key discussion items include feasibility of teaching problem solving skills, types of modifications needed, and the generality of these skills to novel formats.