Students with disabilities are frequently granted accommodations for high-stakes standardized tests to provide them an opportunity to demonstrate their academic knowledge without interference from their disability. One type of possible accommodation, test response format, concerns whether students respond in multiple-choice or constructed-response format. An experimental study was conducted to assess the performance differences of third-grade students with mathematics difficulty on a test of mathematics problem solving as a function of response format. Students responding in the multiple-choice format had a significant advantage over students answering in the constructed-response format. (Contains 2 tables.)