This survey-based study, conducted in the peak of the COVID-19 pandemic, focuses on the impacts of social media-based discrimination on youth of color. In particular, the study looked into the engagement of youth of color in racial justice movements on social media, proposing that: (1) different types of social media use may be associated with increased risks of depression symptoms, anxiety symptoms, and substance use; (2) individual versus vicarious (to others of the same racial group) discrimination on social media may mediate the association between different forms of social media use and the consequential mental health and substance risks.