Background/purpose: Moral leadership is essential to foster ethical, effective school management and create positive educational environments. Existing moral measurement instruments focus on general morality, and there is a lack of tools tailored to assess the moral leadership of prospective primary school principals in Indonesia. This study aims to develop and validate Bafadal's Leadership Morality Questionnaire (BLMQ) to measure the moral leadership qualities of prospective elementary school principals based on spiritual, national, and human morality aspects. Materials/methods: The instrument development followed these steps: (i) content validity was assessed by two experts, (ii) a readability test was conducted with 100 respondent teachers, (iii) an assessment of the internal structure, and (iv) a reliability test involving 362 teachers from East Java, Indonesia, who were selected using multi-stage random sampling. Results: Content validity, assessed by two experts, demonstrated perfect alignment between moral variables, aspects, competencies, and items, with an inter-rater agreement index of 1, requiring no item elimination. The practical evaluation highlighted exceptional usability, achieving a perfect Kappa index of 1.000 (p < 0.01). The readability test confirmed the instrument's clarity. Confirmatory Factor Analysis (CFA) validated the instrument's hierarchical structure, with the third-order model showing the best fit (e.g., RMSEA = 0.074, CFI = 0.915). Of the 65 items, 52 were validated with strong factor loadings (>0.5), while 13 items were excluded for enhancement. Reliability testing revealed high internal consistency, with Cronbach's Alpha and Composite Reliability exceeding 0.9 for most aspects. Norms established using percentile scores classified moral leadership into high (P75 and above), moderate (P50-P75), and low (below P50), providing a robust framework for assessment and intervention. Conclusion: The validated BLMQ offers a reliable and comprehensive instrument for measuring moral leadership in prospective school principals, contributing to their leadership development, classification, screening, and placement in primary education.