This study examines essential elements of school culture in global contexts by applying Schein’s model of organizational culture and interpreted through principals’ voices. The elements were defined on account of the Teaching and Learning International Survey’s (TALIS 2018) five themes: school leadership, school climate, innovation, teacher feedback and development, and job satisfaction. Factor analysis was utilized to find relevant factors of the five themes and content analysis to describe the essential elements based on the factors found. Basic underlying assumptions as well as espoused beliefs and values, the fundamentals of any culture in the Schein’s model, are related to essential elements of inner dynamism and ensuring professionality. Inner dynamism manifested as ambition and principals’ job satisfaction, and ensuring professionality as principals’ responsibilities and activities as well as improvement and strengthening teachers’ professionality. Importantly, the essential elements are interconnected and place special demands on school development and evaluation in diverse global contexts.