The present study investigates the correlation between teachers' implementation of Universal or Learning (UDL) in Mathematics and English/language arts (ELA) instruction and students' performance as measured by the state-wide standardised tests. Teacher participants included ELA and Mathematics teachers in grades 3-8 from a district in the United States in which the UDL framework had been adopted as a system-wide initiative. Student participants included all students in grades 3-8, including students identified with a disability, who took the state's standardised tests. In correlational analyses, findings showed a positive relationship between teachers who had higher UDL implementation scores and students who obtained higher standardised tests scores than the students of teachers who had lower UDL implementation scores.