Purpose--This paper seeks to explore principals leadership in successful Indonesian secondary schools from the perspectives of multiple sources of data. Design/methodology/approach--Inspired by the ISSPP, three schools which met the set criteria of successful schools were selected to be the cases for this study. Within each, individual or group interviews were conducted with the principal, vice-principal, three teachers, one support staff member, two groups of students, one group of parents, and the school committee president. The collected data were transcribed, coded and categorized following the emerging themes, and interpreted using inductive and deductive methods. Findings--Whilst confirming several common practices of successful school leadership from earlier research, the principals from the three successful schools in Yogyakarta also demonstrated significant differences, particularly in terms of beliefs and values that underpinned their leadership. These values include Islamic and cultural beliefs and values which were strong and enduring, and which were articulated in the school leadership and strategies. The principals demonstrated ability in developing the school vision, setting strategies, building capacity, and establishing a broader network to achieve the benefits of school improvement. Originality/value--The paper provides an insight into school leadership practices in the Asian context, particularly in Indonesian Muslim schools, which have suffered from a lack of attention from international researchers. The paper will also contribute to a worldview of successful school leadership characteristics and practices, the research into which has been piloted in the International Successful School Principalship Project (ISSPP). (Contains 1 figure and 3 notes.)