AbstractThe coronavirus disease 2019 (COVID-19) pandemic has had a global impact on children’s education. In Amagasaki City, Japan, elementary and junior high schools were temporarily closed for approximately three months during the pandemic. This study examines the effects of the COVID-19 pandemic on academic performance in mathematics and the Japanese language among public elementary and junior high school students in Grades 1 to 8. Using data from the Amagasaki City Survey of Academic Achievement and Life Conditions from 2018 to 2021, this study compares changes in the academic performance of cohorts with and without COVID-19 experience (the COVID-19 and non-COVID-19 cohorts, respectively) 7 and 19 months after school closures using the difference-in-differences method. The findings indicate that the negative impact of the pandemic on academic performance was more pronounced for math than for the Japanese language, both at 7 months and 19 months after the closures. Math scores showed considerable decreases of 0.133 standard deviations (SDs) and 0.249 SDs at 7 and 19 months after the closures, respectively, while Japanese language scores were not significantly affected 7 months after closures but decreased by 0.113 SDs at 19 months after the closures. Furthermore, the negative effects on Japanese language scores were more significant for individuals in younger grades, whereas math scores were consistently affected across all grades. These results have important implications for policymakers and educators struggling to overcome the learning losses among children caused by the pandemic.