Recognizing that English skills are vital for international communications, for the economic development of the country, and for Thailand to compete with other nations, the Thai government has formalized the teaching of English in its Basic Education Curriculum. In 1999, the Ministry of Education reformed and decentralized the Thai educational system with the National Education Act B.E. 2542 (A.D. 1999). In 2001, the Ministry of Education issued an English Program Policy allowing qualified schools to teach certain subjects under the Basic Education Curriculum in English as an alternative mode of instruction. This mixed method research investigated the implementation of the English Program Policy of three Secondary Schools under the Secondary Educational Service Area Office 7. Instruments used was opinionnaire surveys adopted from the Office of Basic Education Council (OBEC) English Program Educational Standard Educational Institution Self-Assessment Questionnaire and the English Program/ Mini English Program Implementation Student Questionnaire and selected validated questions from studies by Chantarasiri, and Senachit. Respondents were administrators from the Secondary Educational Service Area 7 Office and from the three selected schools with English Program, and teachers and students from the mentioned schools. The data analysis from this study showed that the level of implementation of the English Policy among administrator was Very High, while the level of implementation among students was High. There was no significant difference in the level of implementation among administrators and teachers, and the study found no significant difference in the level of implementation among teachers when compared by the number of years in the position.