For many decades in Southeast Asian art history and archaeology, scholarship has tended to conflate Buddhism with Dvāravatī—the supposed political and/or cultural hegemony of Dvāravatī has at times been plotted according to the locations of material evidence for Buddhism. This paper addresses the issue with regard to Buddhist boundary markers (sema). These large, worked stones, which can exhibit exquisite carvings of Buddhist narrative art, first appear on the Khorat Plateau—which today composes northeast Thailand and central Laos—from the seventh Century CE onwards. They are the most tangible, widespread, and durable evidence for the existence of Buddhism in the region. The tradition continues to evolve on the Khorat Plateau over the eighth and ninth centuries with over 100 sites documented to date. The question remains, however: does their presence also represent the spread of Dvāravatī? In this presentation, I review the available evidence to date and show that the connection between Buddhism, Dvāravatī, and sema stones is more multifaceted than may have previously seemed.