The COVID-19 pandemic is the largest social and economic shock of our lifetimes. As governments grapple with their responses to the virus, more than half the world's countries have closed their schools and severely limited almost all forms of public life. This will have a profound impact on children, both now and in the decade to come. As many countries start to send children back to school, a question arises: who should go back to school first? This Viewpoint addresses that question in the context of a middle-income country, South Africa. Based on a review of much of the evidence available at the time of publication, it concludes that the youngest children are least susceptible to harm from COVID-19, are less likely to spread the virus than adults, and also have the most to lose by being out of school. Hence, they should be the ones to return to school first.