In the EIS project Thai teachers instruct their classes (Science, Mathematics, Computer and English) in English language using English textbooks. The low amounts of tuition fees paid by the students are used to train the Thai teachers to use English as a medium of instruction. Then Teachers improve their skills by on-the-job-training and students improve their English language skills in the new created English environment. EIS is based on a mix of applying the Human Resource Development (HRD) theory and the Sufficiency Economy Philosophy (SEP) of His Majesty the King Bhumibol. The mix of developing a human being in the aspects of economic, system and psychology with respect to the spiritual aspect of Thai culture; reasonableness, moderation and self-immunity creates sustainable knowledge and it will ensure that the teachings of Buddha will be maintained.