Assessment of students' learning in school is deeply implicated in teaching for social justice. Yet classroom assessment is neglected relative to other aspects of curriculum and pedagogy in the literature on teaching for social justice. Some books have a relatively clear theory of anti-oppression education at their core but do not provide details about the links between assessment and their anti-oppression theory, while others provide a more detailed view of assessment practices but do not specify precisely how particular assessment strategies either promote or hinder anti-oppression education. This article provides a theoretical framework that spotlights key links between teaching for social justice and classroom assessment. To illustrate these connections, we draw on guided group discussions with ten high school social studies and English teachers, interested in pursuing professional development in this area. We conceptualize assessment as a set of institutional processes with the potential either to inhibit or nurture the development of young people as well as their capacity for self-determination. We analyze: (a) how teachers, through various assessment practices, can attempt to enable equitable relations within and beyond the classroom; and (b) performance standards aimed at helping teachers assess their students' progress toward becoming more socially responsible and, ultimately, more self-determining. We conclude that even as teachers struggle to enact more socially just assessment practices, they need to communicate clearly with students and parents about what constitutes equitable assessment and what institutional practices, by contrast, sow seeds of self-doubt and lead to destructive labeling, ranking, and gate keeping.