This paper examines how state-led nationalism in Vietnam has been constructed, mobilized, and deployed as both a cultural and developmental project since reunification in 1976. Drawing on modernist and constructivist theories of nationalism, it argues that nationalism in Vietnam functions as a deliberate state strategy to legitimize authority, foster cohesion, and shape economic development. Using symbolic nationalism as the main analytical lens, the paper traces how the Party-state has institutionalized unity through three domains: myth and place-making, standardized education, and digital nationalism. Empirical illustrations such as the ritual veneration of the Hùng Kings, national curriculum reforms, and coordinated online campaigns reveal how symbolic tools produce a sense of shared identity while reinforcing political legitimacy. However, the analysis also highlights the uneven operation of these strategies across Vietnam’s regional and cultural divides. Provincial disparities in income, migration, and literacy demonstrate that state-led nationalism has projected unity more effectively than it has achieved substantive regional convergence. The paper concludes by identifying methodological challenges in measuring nationalism as a multidimensional and politically sensitive phenomenon, proposing the development of a composite “state-led nationalism index” that integrates cultural, institutional, and spatial indicators. Vietnam’s experience thus illustrates both the integrative potential and the inherent fragility of nationalism as an instrument of modern state-building and development.