This study examined the relationship of self-concept, school belonging, school engagement to school performance of Caucasian- and African-American students. The main purpose is to assess the ethnicity-based differences in these psycho-social constructs and to explore their differential relationship to school achievement in high-school students from different ethnic background. The data were collected through a survey questionnaire in three school divisions in the Southwest region of Virginia of the United States. The results showed significant ethnicity-based difference in self-concept and in school engagement, but no significant difference in school belonging. The achievement differences were also significant, Caucasian students being higher on self-reported grades. In the regression model, self-concept was not a significant predictor of school outcomes, while school belonging had a significant relationship to school achievement for African-American students. Both self-concept and school engagement were significant for Caucasian students. The findings of the study provide better understanding of the relationship of these variables to school achievement and point to some policy-relevant implications.