There is debate around offering ethnic studies to high school students. Ethnic studies connects learning to students' lives and analyzes the workings of racism to construct avenues toward equity. As the debate unfolds, it is critical to examine ethnic studies' implications for youth development and the mechanisms that link it to student outcomes. One of ethnic studies' long-stated goals is fostering students' critical consciousness. Critical consciousness refers to critical reasoning around inequality (critical reflection), motivation to challenge inequality (critical motivation), and action taken to disrupt inequality (critical action). Little research has examined youth critical consciousness development within ethnic studies-a consciousness-raising system. Consequently, this longitudinal mixed-methods study examines students' critical consciousness development in ethnic studies and sheds light on the contextual characteristics (i.e., critical school socialization) that foster critical consciousness. Analyses of 459 ninth-grade students' (52% girls, 4% nonbinary; 1% Asian, 1% Black, 4% multiracial, 64% Latinx, 7% Native American, 15% described their own race, 7% skipped the question; Mage = 13.92) survey data, and focus group data with 19 students, revealed that ethnic studies-enrolled students grew more in their critical reflection than nonenrolled students. However, the quantitative data demonstrated decreasing critical motivation among all students, whereas the qualitative data suggested emergent critical motivation among ethnic studies-enrolled students. Furthermore, critical school socialization and teacher pedagogy were key to ethnic studies consciousness-raising. Altogether, this study highlights that ethnic studies fosters youth critical consciousness-a worthwhile outcome that should be considered in policy debates about ethnic studies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).