Abstract: This paper examines the securitization process of unauthorised migration in Thailand, in particular how the cross-border flows of marginalised minorities, the so-called ?hill tribes? came to be seen as an ?existential threat? to Thai national identity by the state. The paper aims to present a case of societal security by highlighting the importance of national identity. It intends to explore the reasons for portraying cross-border mobility of border minorities as existential threats to the integrity of the Thai state. More specifically, it will investigate the motives of the securitising actor, the Thai state ? and examine why the issue evoked security concerns in the wake of the 1997 economic crisis and the way ?emergency measures? were introduced. This paper will illustrate the importance of ethnocized discourses on national identity by broadening the traditional security studies? framework on states and political-military competition at the borderlands.