The three southernmost provinces of Thailand, namely Pattani, Yala, and Naratiwat, are unique in many ways. First and foremost, the three provinces comprise the largest Muslim populations in the country. In terms of language, the Pattani dialect of Malay is a mother tongue for most people in the area, differing from other parts of the country, where Thai language is used. For long, the differences in language used have been an issue of concern for the Thai government. Earlier, under the strong nationalistic and assimilation policy, not knowing Thai language was a threat to national sovereignty, the strategies used to promote Thai language were coercive and uncompromising. Meanwhile, the use of Malay language in schools was prohibited. However, the situation has changed. Recently, there has been an increasing use of Malay language as a medium of instruction in several government-initiated projects. What are the reasons behind this change? This article aims at examining the policy on language of instruction in schools in three southernmost provinces of Thailand from 1932 to present. The data used for this article are based on the examination of documents and interviews with officers in the region. Compared to the strict prohibition on the use of Malay language in schools in the past, the recent shift of policy which accepts the use of Malay language as a medium of instruction in schools seems to recognize the cultural identity of Muslim students as parts of the education system in the country.However, the article argues that the real impetus for such policy is rather for security purposes, just like it was in the past. Thus, the permission to use Malay language in schools may be temporary.