This article is a cross-case study exploring two young African-American adolescent girls' experiences with school mathematics and the impact of the socio-cultural context upon their motivation and mathematical identity. Based on repeated in-depth interviews and ethnographic observation of their mathematics classroom, the researcher portrays contrasting pictures of two sixth-grade African-American girls who are ironically faced with the same end-of-the-year-results despite their differing personal and academic profiles. Overall data analysis reveals the profound impact of ethnicity and class, especially the influence of cultural and social capital, upon the girls' experiences with school mathematics as well as their construction of identities in the discipline. Applying social constructivist approaches to motivation, Ogbu's theory of involuntary minorities, and cultural reproduction theory, the researcher discusses possible variation and complexity existing in African-American girls' experience with school mathematics and calls for more thorough, in-depth examination of race and gender issues in mathematics education. (Contains 1 note.)