Despite a growing literature on immigrant concentration in schools and student outcomes, the effects on adolescent crime has received surprisingly little empirical focus. This study addresses the effect of immigrant peer exposure in schools on later criminal behavior among male students using Norwegian administrative data. Our sample covers eighteen full cohorts in their final grade of compulsory education (age 16) followed to their early twenties (448,332 students; 13,521 school-cohorts; 1,011 schools). Results show a positive correlation between immigrant share and crime rates at the school-cohort level (Pearson’s r = 0.240, p < 0.001). While this relationship is strongly reduced in regressions controlling for school fixed effects and student background characteristics, we find that students graduating from cohorts with higher shares immigrant peers within the same school are slightly more prone towards criminal behavior in adolescence. Effects are stronger among students with less-educated parents, and primarily found for damage-, drug-, and property-related crimes. Effect sizes are, however, modest in substantive terms: a within-school SD increase in immigrant share (i.e., 2.5 pp or less than 3 immigrants in an avg. cohort of ~90 students) is related to an overall 0.2-0.3 pp (~1.5-2.5%) increase in predicted crime probability. Overall, our results suggest that school-level correlations between immigrant share and adolescent crime primarily reflect sorting of families with less socioeconomic resources and higher latent crime propensities into the catchment areas of immigrant-dense schools in Norway.