This study aimed to investigate how data are used to inform instructional leadership practices in three Kuwaiti public schools, in addition to the factors that impact building data-use capacity. This study conducted three qualitative case studies in high-performing public schools. The findings reveal that data usage in the Kuwaiti schools facilitates the diagnosis and mentoring of students' academic performance, instructional supervision and change, and the establishment of new plans and activities. Furthermore, the factors helping and hindering the data-use capacity were also assessed.