This study used modified schema-based instruction (MSBI) to teach mathematical word problem solving to three students with ASD in fifth and sixth grade. Following explicit strategy instruction, the participants learned to use an 8-step task analysis and a graphic organizer to solve and discriminate between math word problems requiring algebraic reasoning. A multiple probe across participants design was used to establish a functional relation between MSBI and word problem solving, with a non-parametric measure (Tau-U) confirming visual analysis of a large effect (0.87). Results indicated students increased the number of steps of the task analysis solved independently correct, total problems solved, and discrimination of problem type. Implications for practice and future research are discussed.