We conducted a secondary analysis of cross-sectional data to examine the association of cumulative trauma, post-traumatic stress disorder (PTSD), and substance use disorder (SUD) with the probability of arrest in a sample of socioeconomically disadvantaged African American and Latino mothers ( N = 158). Results revealed that 34% of the sample had a history of arrest. Logistic regression revealed that cumulative trauma was significantly and positively associated with the likelihood of arrest. Exposure to increasing numbers of traumas contributed to greater odds of arrest, as much as 62% for each additional trauma exposure. Moreover, binary mediation analyses revealed that PTSD and SUD exerted an intervening influence on the pathway between cumulative trauma and the probability of arrest. Women with a lifetime history of PTSD or SUD were 5–6 times more likely to be arrested than women without either disorder. Lifetime PTSD and lifetime SUD were partial mediators of the association between cumulative trauma exposure and arrest, accounting for 63% of the variance. These findings have important implications for intervention efforts geared toward helping young racial/ethnic minority mothers, especially those with PTSD and SUD, manage the distress and impairment that may contribute to criminal justice involvement.