This paper examines the impact of international students on the academic outcomes of domestic peers in introductory economics courses. We address the potential endogeneity of class selection by focusing on first-year students enrolling in a large public flagship university, for whom class assignment is likely to be quasi-random, conditional on a rich set of control variables for the class and individual. Results suggest an increased share of international student peers reduces the likelihood of majoring in economics for domestic White and Asian men while increasing the likelihood of majoring in economics for domestic men from underrepresented racial and ethnic groups. There is also evidence that higher shares of international student peers increase the likelihood that domestic White and Asian men major in business and decrease the likelihood that some men drop out of college. Additional analyses point to introductory course grades as possible mechanisms to explain these results, as a higher international peer share is associated with higher domestic student grades. Results for men enrolled in large introductory economics classes are similar to the main results for men overall and are also similar for women.