Based on sociological, economic, and social-psychological theories of discrimination and bias, this study addresses non-native accents among ethnic minority students as they begin school and explores effects of such accents on their teachers' achievement expectations. Using a unique data set of first graders in Germany, the analysis reveals that a non-native accent is relevant to teachers' expectations net of student skills, abilities, and other background variables. Associations are stronger in the language domain than in mathematics, indicating that teachers perceive accent-free speech as a language-learning requirement. However, residual influences of non-native accents on teacher expectations also exist in the math domain and persist even after prolonged periods of teacher-student interaction. Mechanisms of statistical discrimination and stereotype-based discrimination can partially explain these effects. However, the overall pattern of results suggests a stigmatization of non-native accents, potentially resulting from the activation of negative associations related to foreignness and disfluency.