In 1994, South Africa emerged as a leader in tobacco taxation among middle-income countries. From 1994 to 2009, sharp excise-tax increases, complemented by progressive tobacco-control legislation, led to major declines in smoking and significant revenue gains. However, since 2010, many of these gains have been reversed. The entry of small, locally based tobacco companies disrupted a previously stable market and contributed to a surge in illicit trade. Institutional failures, exacerbated by the tobacco industry’s underhanded tactics, at the South African Revenue Service between 2014 and 2018, and the industry’s conduct during the 20-week tobacco sales ban in 2020, further entrenched the illicit market. Since 2020, more than half of all cigarettes sold in South Africa are illicit, severely undermining tobacco taxation and other tobacco-control attempts. This paper offers a historical perspective on tobacco taxation in South Africa, to highlight lessons for other countries. It demonstrates that while well-designed tax policy can yield major health and revenue benefits, sustained success requires vigilance. An excise tax approach that targets tax incidence (ie, total taxes as a percentage of the retail price) must account for industry pricing strategies and allow for timely policy adjustments. Long-term effectiveness also hinges on strong enforcement, transparent supply chain regulation and safeguarding policy processes from industry influence. Across all aspects of tax policy, South Africa’s experience underscores the need for governments to remain alert to an industry that will exploit any weakness for profit. Complacency can swiftly undo years of progress.