If children fail to understand test instructions, measurements of their competence may be unfair and invalid. This is especially relevant for students with special educational needs (SEN) because they face greater challenges in comprehending instructions. Two interventions were designed to facilitate the comprehension of test requirements by presenting intensified instructions and to enhance students' attention by engaging them in physical activity before receiving the test instructions. Three-hundred forty-eight students with SEN aged 8-12 years were randomly assigned to an experimental condition or a control group. Even after controlling for relevant variables (reading speed, basic cognitive skills), students participating in the interventions performed better in a reading test than controls. As hypothesized, the intensified test instructions reduced the number of responses that were not compliant with instructions. In conclusion, this study shows the importance of adapting test instructions for students with SEN, and it proposes interventions that can be implemented in other assessments.