The principal as a reflective leader plays a critical role in today's fast-paced school environment. Although the growing role of principals in improving decisions through reflection, few researchers have studied the reflective habits of the minds that involved principals. Hence, the study intends to review existing literature on reflective habits of the minds among principals and to track what was contributed to understanding reflection and its effect on ethical leadership and decision-making. A comprehensive search of major databases was undertaken which identified 32,896 studies on the topic; 13 met the inclusion criteria. Using a systematic literature review, data were extracted and analyzed using thematic analysis. Three themes emerged from the analysis: reflective habits for teaching and learning, reflective habits for professional development, and reflective habits towards authentic and transformational leadership. Studies focused on the heart of the reflective practice of school principals as an instructional leader as a critical tool for learning and professional growth. It also shows the inspiring ways of how authentic and transformational leadership through reflective practice could change the educational system. As a result, the literature review pointed to the following discussion points, which are the areas that require further research: (1) diverse reflective practices among school principals in instructional leadership, (2) continuous reflective professional development activities, and (3) reflection-inaction towards transformational leadership.