Introduction – Every year since 2016, Santé publique France has launched the “Smoke-Free Month” initiative, which encourages smokers to quit smoking for 30 days in November. The purpose of this article is to present an estimate of the health and economic impact of this campaign. Method – The study is based on the Strategy Planning for Public Health on Noncommunicable Diseases (SPHeP-NCD) model developed by the Organization for Economic Cooperation and Development (OECD). The impact of the “Month Without Tobacco” initiative was estimated by comparing the outcomes of a status quo scenario (without implementation of the initiative) with a scenario in which “Month Without Tobacco” is implemented annually over the period 2023–2050. Results – By 2050, the Tobacco-Free Month campaign is projected to prevent: 241,000 cases of lower respiratory tract infections, 210,000 cases of musculoskeletal disorders, 44,000 cases of chronic obstructive pulmonary disease, 28,000 cases of tobacco-related cancers, 18,000 cases of cardiovascular disease, 8,000 cases of dementia, and 4,000 cases of diabetes. It would save 107,000 life years and 149,000 disability-adjusted life years, save an average of 94 million euros per year in healthcare costs, and increase employment and labor productivity by 2,800 full-time equivalents per year, with an estimated value of 85 million euros (compared to an average annual cost of the “Month Without Tobacco” campaign of 12.5 million euros over the 2016–2021 period). Conclusion – The return on investment for the Tobacco-Free Month campaign is highly favorable, with approximately €7 in healthcare costs saved for every €1 invested. These results provide strong incentives to continue rolling out this important public health initiative.