This study reports high school Black girls' experiences in mathematics classrooms. Forty-eight Black girls participated in 12 focus groups. Findings showed that the girls experienced uncaring teachers, uninteresting curriculum, and unsupportive learning environments. We used a sociopolitical analytic approach to make sense of their narratives and theorized how these experiences could relate to discourses of intersectional harm. We argue that discourses of (1) silencing and dismissiveness and (2) erasure of intellect manifested in their mathematics classrooms and served as barriers to their positive mathematics identity development. We propose a vision for disrupting these discourses of intersectional harm.