This study aims at understanding how Rwandan high school principals lead and manage their schools, drawing on concepts of school culture. The research focuses on educational leadership and management in a post-conflict country which is still rebuilding following the 1994 genocide. The author intends to provide an original contribution to the field of education, notably in establishing how Rwandan high school principals exercise their responsibilities. The study is exploratory and explanatory research that focuses on how principals collaborate with partners, facilitate and participate in the development, implementation, and stewardship of a vision of learning that is shared, supported and owned by the school community. The main focus is on how the principals advocate, nurture, and sustain a school culture and instructional plans conducive to students’ learning and staff professional development. Data collection followed a mixed-methods approach, quantitative and qualitative, and consisted of two phases, the first being survey research, using a questionnaire, and the second being a case study approach with two secondary schools. The survey was adapted from Phillips and Wagner’s (2003), and Wagner and Masden-Copas’ (2002), model of School Culture Triage Survey. It was intended to quantitatively explain how the leadership and management of the school principal impacted on school culture, while the semi-structured interviews, within the case studies, were designed to explore the school principal’s leadership and management from a range of perspectives. These two phases were conducted using different research tools. The first phase of data collection was conducted by administering semi-structured interviews with the principals of all 14 high schools in the Huye District. In this phase, all the 14 participants had the same interview schedule, which targeted the role of these principals in leading and managing their schools. The interview schedule was structured but also provided potential for probes and prompts. The survey was followed by the two case studies, the highest and lowest ranked schools in the survey. The case studies aimed to explore the main responsibilities of the principals, how they relate to other stakeholders, and how they lead and manage staff and other resources. Data were gathered through semi-structured interviews with eight participants in each school, via documentary analysis, and through shadowing the two principals. The quantitative data were analysed using descriptive statistics while qualitative data analysis followed a thematic approach. The findings show that principals in the Huye district of Rwanda are constrained by a centralized education system with predetermined rules and mandates from higher authority. The results also demonstrate that they have little autonomy and limited participation in decision-making on curricular and pedagogical issues. A review of the traditional top-down, hierarchical and managerial leadership is required to enhance school-based leadership and management.