Police stops are a pervasive form of criminal justice contact among adolescents, particularly adolescents of color, that have adverse repercussions for mental health. Yet, the mental health consequences of adolescent police stops likely proliferate to parents of adolescents exposed to this form of criminal justice contact. In this article, I conceptualize adolescent police stops as a stressor, drawing on the stress process perspective to examine how and under what conditions this form of criminal justice contact damages the mental health of adolescents’ mothers. The results, based on data from the Fragile Families and Child Wellbeing Study, suggest three conclusions. First, the mental health consequences of adolescent police stops proliferate, increasing the likelihood of depression and anxiety among adolescents’ mothers. These relationships persist across modeling strategies that adjust for observed confounders, including adolescent characteristics such as delinquency and substance use. Second, the relationship between adolescent police stops and mothers’ mental health is contingent, concentrated among mothers with prior exposure to the criminal justice system (either via themselves or their adolescents’ fathers). Third, mothers’ emotional support buffers the relationship between adolescent police stops and mothers’ mental health. Taken together, this research highlights the role of police exposure as a stressor that is experienced vicariously and that has contingent consequences and, accordingly, documents the expansive and proliferating repercussions of police contact. Given the concentration of police contact among marginalized adolescents, including adolescents of color, these findings highlight another way the criminal justice system exacerbates structural inequalities.