Although the number of deaths worldwide from tuberculosis—a disease caused by the bacterium Mycobacterium tuberculosis—fell by 22% between 2000 and 2015, it remains humanity’s biggest infectious killer and one of the top ten causes of all deaths. The 2016 WHO Global Tuberculosis Report estimated that in 2015 there were 10.4 million new tuberculosis cases and 1.4 million deaths. The interaction between tuberculosis and HIV is important, with an estimated 400 000 additional deaths occurring among people with co-infection. Perhaps most troubling, is that the new cases of tuberculosis include about 480 000 people with the multidrug-resistant form of the disease—that is, resistant to treatment with two of the first-line medications against tuberculosis, isoniazid and rifampicin. Only about 20% of people newly eligible for treatment for multidrug-resistant tuberculosis in 2015 were enrolled in treatment. One of the UN Sustainable Development Goals for 2030 is a 90% reduction in tuberculosis deaths and 80% reduction in new cases (incidence) compared with 2015. However, the current annual rate of decline of incidence is only 1.5% and needs to reach 4–5% for the milestone to be achieved. Furthermore, unless investment in tuberculosis treatment and prevention increases, there will be a US$6 billion funding gap by 2020. Tuberculosis remains a treatable disease—even the multidrug-resistant form, albeit with a complex and time-consuming drug regimen. Although it is primarily a disease of poor and disadvantaged people, everyone on Earth is potentially at risk of tuberculosis. World TB Day is an opportunity to highlight the challenges—and opportunities—to achieve the goal of controlling tuberculosis through sustained prevention, detection, and treatment.