The school closures owing to the 2020 COVID-19 crisis resulted in a significant disruption of education provision, leading to fears of learning losses and of an increase in educational inequality. This article evaluates the effects of school closures based on standardised tests in the last year of primary school in the Dutch-speaking Flemish region of Belgium. Using a 6-year panel, we find that students of the 2020 cohort experienced significant learning losses in three out of five tested subjects, with a decrease in school averages of mathematics scores of 0.17 standard deviations and Dutch scores (reading, writing, language) of 0.19 standard deviations as compared to previous cohorts. This finding holds when accounting for school characteristics, standardised tests in Grade 4 and school fixed effects. Given the large observed effect sizes, the effect of school closures appears to be a combination of lost learning progress and learning loss. Moreover, we observe that inequality both within schools and across schools rises by 7% for mathematics and 8% for Dutch. The learning losses are correlated with observed school characteristics, as schools with a more disadvantaged student population experience larger learning losses.