Large scale educational assessments conducted in the United Arab Emirates (UAE) show a substantial gap between the performance of different types of schools. This study used the 2015 Program of International Student Assessment (PISA) to investigate how student- and school-related variables accounted for the variation among schools. The results showed a varied influence of the variables in each type of school. Student-related variables were more strongly associated with students' performance and accounted for most of the between-school variation. The findings indicated the diversity of students enrolled in different schools and suggested the importance of providing equal opportunity of learning that calibrates to the differences in student backgrounds and needs.