In the current study we examined the effect of a self-regulated strategy development intervention on the fraction calculations of students with or at risk for disabilities using a multiple-baseline-across-sites, single-case design. Specifically, the intervention package addressed the following skills: adding and subtracting fractions with unlike denominators, simplifying fractions, and converting improper fractions to mixed numbers. The intervention was implemented with high levels of treatment fidelity and social validity across three separate intervention agents. Results of the study showed the intervention to be effective, with 15 of the 16 participants making marked gains on fraction probes. We discuss the results of the study with respect to the research questions, provide limitations to the study, and propose areas for future research.