Ethnic identity is a reflection of an individual’s own ethnic group membership and interaction with members of other groups. This study examined the relationship between students’ ethnicity, general school self-concept, school attitudes, and academic performance measured by self-reported responses. The sample was made of low-income, high-ability African American and Hispanic 7th and 8th grade students, N = 186, that participated in a residential summer academic program. A path model was proposed with four components to measure academic achievement: ethnic identity, school attitudes, general school self-concept, and self-reported GPA. The path analysis model explained 11% of the variance in GPA and revealed one direct effect on GPA: school attitudes. Ethnic identity was indirectly linked with GPA through school attitudes. The effect of ethnic identity on GPA was indirectly associated with school attitudes (p < .01). Understanding students’ backgrounds and increasing their ethnic identity may contribute to providing a positive school experience to low-income diverse ethnic student groups and reducing the achievement gap.