This paper provides first-hand evidence that chronic absenteeism (the share of students who miss 10% of classes or more during a school year), increased drastically in low-and middle-income countries like Brazil after the pandemic. Drawing on official attendance data for the universe of students whose households are eligible for Bolsa Família – the country’s flagship conditional cash transfer program –, we document that chronic absenteeism nearly doubled in 2022-23 relative to 2018-19, now affecting ~23.3% of low-income students and still on the rise even after in-person classes resumed. A novel nationally representative survey documents that such patterns are similar in the general student population. Using a triple-differences strategy, which contrasts public to private school students within municipalities in São Paulo State that authorized the former to resume in-person classes already in 2020 vs. those that did not reveals that, different from the US, returning to in-person classes earlier caused higher chronic absenteeism after the pandemic – inconsistent with the latter being driven by the erosion of attendance norms. Rather, students report recurring health issues and lack of motivation in face of dramatic learning losses as the most common reasons for missing classes.