The COVID-19 pandemic is a blow to an already fragile global economic outlook. The health crisis, sharp downturn in activity, and turmoil in global financial markets caught emerging market and developing economies at a bad moment. The past decade has seen the largest, fastest, and most broad-based increase in debt in these economies in the past 50 years. Since 2010, their total debt rose by 60 percentage points of GDP to a historic peak of more than 170 percent of GDP in 2019. Although China accounted for the bulk of this increase—in part due to its sheer size—the debt buildup was broad-based: in about 80 percent of these economies, total debt was higher in 2018 than in 2010. Even excluding China, debt rose by 20 percentage points of GDP, to 108 percent, in 2019. As these economies respond to the pandemic, their debt will only increase. The current global recession is unusual in its severity. Like previous crises, it is testing the resilience of heavily indebted countries and companies. What policies do highly indebted emerging market and developing economies need to implement to mitigate the damage of the pandemic and support a durable recovery? History can give policymakers some useful pointers.