ABSTRACT. Systemic racism exposes Black and Latinx adolescents to a range of traumatic stressors, including publicized instances of police brutality toward Black people, stressful personal interactions with hostile police officers, and oppressive immigration policies. The combination of systemic racism and the coronavirus-19 pandemic (COVID-19)--termed the “twin pandemics”—are placing Black and Latinx adolescents, especially those in under-resourced communities, at particularly high risk for family financial strain, food insecurity, school disruption, and illnesses and deaths of loved ones. Cumulative stressors during the critical developmental period of adolescence increase risk for long-term emotional and behavioral problems into adulthood; thus, it is urgent that we: (1) understand the impact of cumulative race-related stress on marginalized adolescents during and after the pandemic and (2) identify protective factors that promote their resilience and wellbeing. Researchers have theorized that one protective factor may be critical consciousness, or the awareness of societal inequities and activism to promote social justice. We lack rigorous longitudinal research, however, on the development of critical consciousness among marginalized youth, its association over time with emotional and behavioral health (EBH), and its potential to protect again harmful effects of race- related stress. The proposed longitudinal study will assess race-related stress, critical consciousness, and EBH among Black, Latinx, and White adolescents in Baltimore. We will leverage participants and data from an NICHD-funded trial with longitudinal data collected at four time points prior to COVID with ethnically diverse adolescents in Baltimore City. We will augment this sample by recruiting additional Baltimore adolescents, for a total sample of 650 young people ages 14-18, with approximately equal numbers of Black, Latinx, and White participants. We will follow these young people over four years (until ages 18-22). Participants will complete online surveys twice per year assessing race-related stress exposures, critical consciousness, and three domains of EBH (emotional wellness, mental health problems, and substance use). We will conduct in-depth interviews with a subset of Black and Latinx youth and, separately, with their caregivers to gain more insight into how youth engage in critical consciousness/activism and its effects. Qualitative themes will enrich our quantitative analyses on critical consciousness and its potential protection against the harms of race-related stress. We will develop a Youth Advisory Board to engage input from young people in our target population at all stages of this research. Using procedures effective in our prior work, we will also train young people to conduct the qualitative interviews with adolescent participants to enhance trust and rapport. Study analyses will be critical for expanding theory on risk and resilience among marginalize...