Greenfield's subjectivist approach to the construction and interpretation of social reality is examined and applied to school organizations in an attempt to demonstrate that such organizations may be advantageously viewed as entities constructed and sustained by ideas in people's minds. The path to understanding schools and their administration lies with the interpretation and analysis of the "experience" of people in these institutions rather than in the use of overarching theories of educational management. International schools have always provided education for the ever-increasing flux of people across frontiers, either temporarily because of job postings (globally mobile families) or more permanently because of migration. The high degree of cultural diversity in these schools augments the complexity of leadership because staff, students, and parents bring their own cultural heritage, experience, and expectations to bear, together, in a single school setting. This also increasingly applies in government schools in many countries because of migration. Ethnic cultural repertoires play a major role in the creation, deciphering, and juxtaposition of individual social realities and have an important bearing on organization culture. The article concludes with the importance of communicative and cultural competencies as the main tools for effective school leadership in international schools.