This paper is based on a survey of the so-called "sedentarization" of the Mlabri in Thailand. It is argued that for at least three reasons their sedentarization is not a "normal" transition from a hunter-gatherer to an agricultural society, as would be assumed by an evolutionist perspective. First, it does not relate to a "natural" or inevitable pattern because it has been largely a State-led process initiated through development projects. Second, it does not have the same characteristics everywhere, and depends on social networks as well as on historical and geographical factors. That means sedentarization of the Mlabri cannot be fully understood without considering their relationships with other ethnic groups, especially the Hmong. Finally, sedentarization is an open-ended process with no obvious and predetermined end, because the Mlabri interact with their neighbors and the various development projects and still move from one settlement to another one according to their own agenda.