Vietnam’s rapid economic development since the 1986 Doi Moi reforms has been shadowed by a persistent and severe air pollution crisis. This review systematically analyzes the nexus between the evolution of Vietnam’s environmental legal framework and corresponding air quality trends over three decades. Despite the progressive development of a comprehensive legislative architecture, culminating in the Law on Environmental Protection 2020, this study reveals a profound disconnect between policy ambition and environmental outcomes. Ambient concentrations of key pollutants, particularly fine particulate matter (PM2.5), remain dangerously high, consistently exceeding both national standards and World Health Organization guidelines by a significant margin, thereby imposing substantial public health and economic burdens. The temporary air quality improvements during Covid-19 lockdowns starkly demonstrated that pollution levels are dictated more by the intensity of economic activity than by the efficacy of existing regulations. This review argues that the central problem is a critical implementation gap, originating not from inadequate laws but from deep-seated, systemic challenges. These include fragmented institutional governance, a de facto prioritization of economic growth over environmental protection, chronically weak enforcement mechanisms, and a constrained space for civil society to ensure accountability. The pattern of repeatedly revising legislation without addressing these foundational issues has created a “legislative treadmill,” giving an illusion of progress while failing to achieve tangible improvements. The analysis concludes that a fundamental paradigm shift from policy formulation to a resolute focus on robust enforcement, institutional reform, and data transparency is imperative for Vietnam to mitigate this environmental crisis and realize its sustainable development goals.