Asthma is the most common noncommunicable disease in children, and among the most common in adults. According to the most recent estimates from the Global Asthma Network Phase I study, around one in 10 children and adults have symptoms of asthma and one in 20 school-aged children have severe asthma symptoms, with marked variations in prevalence and in prevalence trends between countries and regions of the world. The Global Burden of Disease Study estimated that asthma caused the loss of 21.6 million healthy years of life (disability-adjusted life years) and 461 069 deaths in 2019. Approximately 90% of the asthma burden of disease is borne by people living low and middle income countries (LMICs). Some countries report very high (up to 90%) rates of uncontrolled asthma. While the prevalence of asthma is highest in countries with a high Socio-Demographic Index (SDI), death rates from asthma are highest in countries with low and lower middle incomes.