INTRODUCTIONAs a part of a priority-setting stakeholder engagement project to strengthen the impact of the federal Tobacco 21 (T21) law, we conducted a qualitative study to solicit input from a nationwide sample of tobacco control stakeholders regarding the implementation, enforcement, and equity implications of the T21 law.METHODSFollowing the T21 policy evaluation guidance developed by the Centers for Disease Control (CDC), we identified T21 experts in four domains: policy, evaluation, subject matter, and implementation from a national search of stakeholders (invitations, n=1279) to account for geographical variation. This study presents results from five focus groups conducted in December 2021 among stakeholders (n=31) with experience in T21 policy, evaluation, subject matter, and implementation.RESULTSParticipating T21 stakeholders reported on eight themes from four main topic areas: 1) Implementation, 2) Enforcement, 3) Equity outcomes, and 4) Recommended changes from stakeholders. Stakeholders shared insights on both passive and active implementation methods used in their communities, and highlighted major barriers such as the absence of a standardized tobacco retail licensing mandate and insufficient resources. Regarding T21 enforcement, stakeholders believed that current deterrents for retail violations might not be effective. They noted that vape and tobacco shops and online sales of tobacco products are emerging major challenges in T21 enforcement. Stakeholders also discussed possible health inequities that may be exacerbated by heterogenous implementation of the T21 law.CONCLUSIONSTo strengthen T21 and mitigate potential exacerbation of existing health inequities, greater alignment of federal, state, and local efforts to reduce heterogeneity of implementation and enforcement of the T21 law is recommended.