Students with disabilities often struggle with grade-level mathematics without appropriate support and accommodations. This study compared the performance of middle school students with disabilities on computational-based mathematics assessments when they had access to calculators and when they did not. Using a single-case ABAB design, data were collected on the number of problems attempted, the number of problems (or parts of problems) correctly answered, and, when given access, the number of problems on which students used calculators. In general, students attempted most problems regardless of the availability of a calculator but earned more points when they had access to and used a calculator. Although students indicated positive perspectives in terms of calculator use, most students used a calculator on less than half of the intervention problems. Future research is needed to examine the reasons students choose not to use calculators as well as the specific types of problems they find the calculator most helpful.