["Journal of School Health, Volume 96, Issue 8, August 2026. ", "\nABSTRACT\n\nBackground\nThailand has one of the strongest tobacco control frameworks in Southeast Asia, including comprehensive smoke‐free laws and a ban on e‐cigarettes. However, implementation of smoke‐free school policies remains uneven across diverse educational settings. This study examined the contextual and governance dynamics shaping implementation and sustainability across school types.\n\nMethods\nA qualitative study was conducted using 14 focus group discussions (FGDs) across 14 provinces. Participants (n = 122) included school administrators, teachers, and provincial tobacco control stakeholders. Data were analyzed using reflexive thematic analysis to identify key governance conditions influencing implementation.\n\nResults\nSix interrelated themes emerged: institutional diversity, structural constraints, enforcement gaps, multi‐level enablers, sustainability challenges, and field‐driven recommendations. Implementation gaps were driven less by policy absence than by differentiated governance conditions. Hybrid authority structures, leadership turnover, digital diffusion of e‐cigarettes, and geographic monitoring disparities constrained enforcement capacity. While teacher networks and provincial endorsement enhanced legitimacy, sustainability depended on institutional embedding rather than individual leadership.\n\nImplications for School Health Policy, Practice, and Equity\nUniform national standards require context‐sensitive implementation strategies. Embedding smoke‐free criteria within evaluation systems, institutionalizing peer networks, and addressing geographic inequities are critical to strengthening sustainability and equity.\n\nConclusions\nStrong legislation alone is insufficient; tailored governance approaches are essential to achieve equitable and durable implementation.\n"]