The study delves into the intricate dynamics of educational leadership, teachers job satisfaction, and the mediating role of intercultural competence in the 21st-century school environment. This was conducted among teachers from the international programs in the member schools of Thailands International Institutions Quality Assurance Network (IIQAN). It employed the correlational and causal quantitative research design and utilized descriptive, inferential statistics, and mediation analysis to ascertain the relationship between the extent of utilization of 21st-century leadership styles and the level of job satisfaction. Results reveal that school administrators displayed commendable competence in 21st-century leadership skills. Teachers expressed high levels of job satisfaction related to student behavior, curriculum, and professional development. Consequently, school administrators exhibited strong intercultural competence, facilitating effective cross-cultural interactions. Moreover, effective leadership skills significantly contribute to a positive work environment for teachers. Also, leadership skills and intercultural competence significantly predicted teachers job satisfaction. Finally, intercultural competence fully mediated the relationship between leadership skills and job satisfaction. The study concludes that strong leadership skills, effective communication, and intercultural competence are essential to a thriving educational environment. It further recommends that institutions invest in leadership development programs, encourage administrators commitment to growth, establish open communication channels, and conduct needs assessments for diversity and inclusion.