This paper examines the persistent effect of the 1998–2000 Ethiopia–Eritrea conflict on human capital accumulation. The empirical findings indicate that exposure to conflict during early childhood increases the probability of grade repetition (for boys and girls) and school dropout (especially for boys), and decreases student achievement in mathematics and language scores (mainly for girls) a decade later. Identification of the effect is based on a difference-in-difference approach that exploits temporal and regional variation of the conflict. These effects are robust when including region-specific trends, school, grade, class, and teacher level fixed effects, and other student and family characteristics. The paper provides the first estimates on the long-term effect of exposure to conflict at early (before school-age) childhood on test scores of primary school students.