The discussion of religion and educational development tends to be a neglected topic. This area is particularly important in Thailand because religion is one of the three pillars of the nation. In the centuries prior to the visionary education reforms of King Chulalongkorn the Great to create a modern secular education system, the Siamese education system was basically religious with monks as the teachers and temples as the schools. Later Buddhist universities were developed in the King Chulalongkorn era, which is described. There is then a discussion of how Western missionary influence in the 1800s and early 1900s was important for the development of modern Thai education. Many of Thailand’s elite most prestigious schools are missionary ones such as Assumption and Mater Dei. Then background is provided on Thailand’s religious diversity, followed by a discussion of how certain Buddhist principles relate to progressive education. Among concepts discussed are Buddhist epistemology, modest consumption and the economic sufficiency concept (settakit phophiang) (เศรษฐกจพอเพยง), and impermanence (relates to innovation). Also discussed are Buddhist implications for the curriculum and assessment. Another topic rarely discussed is how religion (both Buddhism and Christianity) can contribute to social mobility. Recent initiatives to have schools more active in promoting Buddhist thought are described. Among these initiatives are the rongrian withiput (โรงเรยนวธพทธ) (Buddhist-oriented schools) and the creation of the Sathirakul Youth Education Foundation. The chapter concludes with reflections on happiness education, core values, and education for optimal living and sustainable development.