This study is concerned with the changing social and political role of religion as a constitutive element in ethnic identity in Malaysia, particularly among the Muslim Malay community. Its concern is both to offer an explanation of these changing dynamics and also to enquire as to how these dynamics might inform our theoretical understanding of 'ethnicity' itself. While Islam has always been a core element of the ethnic identity of the politically dominant Malay population, the period since the 1970s has seen an Islamic resurgence in Malaysia, broadly paralleling those in other parts of the Muslim world over the same period. More recently, however, there has been a notable shift in tenor by the government towards giving Islam a central role in its political and developmental discourse and practice. The paper seeks to explain and understand this shift. Within the context of a stratified political system, Islam and religion, it is suggested, have proved more effective than 'Malayness' and ethnicity as a way to make the population 'legible', while the legal and bureaucratic structures associated with Islam provide a more tenable mechanism of control for the Malay/Muslim population. This points us towards a broadly constructivist understanding of ethnicity that sees it as a domain of contention in which the state plays an important, but by no means pre-eminent, role.