The study presented here tested three theories of racial differences in academic performance among monoracial and multiracial high school students. These theories (status attainment, oppositional culture, and educational attitudes) were developed to explain differences in achievement among monoracial groups, but the study tested how the theories apply to a multiracial sample. The results show that ethnic identity and experiences of ethnic discrimination are not strong factors in explaining academic performance among multiracial or monoracial students. Instead, the grades of multiracial students are related to their concrete beliefs about the consequences of school failure, the educational values of their peers, and the racial composition of their neighborhoods and schools. Additional descriptive statistics found that multiracial students who self-identify as black or Hispanic achieve lower grades than do those who self-identify as white or Asian. The author suggests a transracial theory of academic performance that considers the effects of contexts. (Contains 2 figures, 5 tables and 12 notes.)