This study investigated whether teacher expectations had significant effects on ethnic minority students' second language and foreign language learning in senior high schools. The participants of this study were 52 teachers and 836 ethnic minority students from 10 senior high schools in southwest China. Data of teacher expectations for students' second language achievement, teacher expectations for students' foreign language achievement, students' prior achievement in a standardized test of the second language and foreign language at the beginning of senior high school, and students' achievement in a standardized test of the second language and foreign language at the end of senior high schools were collected respectively. Regression analysis showed that with students' prior achievement being controlled, (1) teacher expectations had significant effects on ethnic minority students' foreign language learning, but (2) teacher expectations were not closely related to ethnic minority students' second language learning, suggesting a moderation effect of the subject. Implications for expectancy theories and multilingual instructions are further discussed.