This multi-case study examines the nature of supervisory practices embedded in the principal evaluation system that supervisors exercise with principals on a weekly basis. Data were collected during the 2018-2019 academic school year in the public schools of the United Arab Emirates. This study relied on several data collection methods, including interviews, documents, and field notes. Nine participants--six principals and three supervisors of principals--participated in semi-structured, face-to-face interviews from which the findings of this study were derived. The analysis of the collected findings yielded five themes related to the experiences of the principals as recipients of supervision: (1) principal supervisors cause fluctuations in the quality of supervision; (2) limited focus on instructional leadership; (3) insufficient supervisory approaches to the developmental levels of principals; (4) fragmented and unfocused professional development; and (5) critical conditions for optimal supervision. The findings of this study have implications for practice and further research that can help leaders and educators establish robust and effective principal supervision systems aimed at improving the quality of school leadership--thereby elevating the core functions of teaching and learning within the school.