This paper analyzes the politics of heritage in urban Cambodia. Focusing on the capital, Phnom Penh, we argue that urban heritage is shaped at the intersection of global doctrines and professional knowledge, socioeconomic strategies at the national and local scales, real estate developments, and contextual institutional practices. We propose the concept “atomization of heritage politics” to explain the fragmentary and tentacular power relations that determine how built heritage is managed or destroyed. Drawing on heritage literature on Southeast Asian cities, we first argue that academic writers underestimate the role of land issues and localized power relations in shaping urban heritage politics. We contextualize the rise of heritage concerns in Cambodia. Since colonial times heritage strategies have focused on the UNESCO World Heritage Site of Angkor, with urban heritage being of only peripheral concern. Second, we explain how proposals made by international development partners for an overall heritage policy failed, as they conflicted with the rationality of land and power relations, leaving foreign consultants to renegotiate their position in Cambodian politics. Finally, we explore two case studies—the National Stadium and the Renakse Hotel—at the center of virulent, long-lasting political clashes between various forces that took root during the reconstruction of the Cambodian state in the 1980s and 1990s. Together with powerful individuals, families, and companies, the competition and tactical alliances between these forces shape the contested politics of urban heritage in the Cambodian capital.