Low levels of education are a powerful predictor of anti-immigration sentiment. However, there is little consensus on the interpretation of this correlation: is it causal or is it an artifact of selection bias? We address this question by exploiting six major compulsory schooling reforms in five Western European countries—Denmark, France, Great Britain, the Netherlands, and Sweden—that have recently experienced politically influential anti-immigration movements. On average, we find that compelling students to remain in secondary school for at least an additional year decreases anti-immigration attitudes later in life. Instrumental variable estimates demonstrate that, among such compliers, an additional year of secondary schooling substantially reduces the probability of opposing immigration, believing that immigration erodes a country’s quality of life, and feeling close to far-right anti-immigration parties. These results suggest that rising post-war educational attainment has mitigated the rise of anti-immigration movements. We discuss the mechanisms and implications for future research examining anti-immigration sentiment.