Our mixed-methods study advances understanding of pathways to offending for jailed women with and without mental illness. Life history interviews with 115 women from five U.S. states examined how onset of crime and delinquency varied based on mental health status and trauma exposure. Women in jails had high rates of mental health disorders, with a majority meeting lifetime diagnostic criteria for a serious mental illness (50%), posttraumatic stress disorder (51%), and/or substance use disorder (85%). Cox regression analyses were utilized to examine associations between life experiences and risk of engaging in specific criminalized behaviors. Serious mental illness was associated with substance use, running away as a teen, and drug offending. Substance use disorder was related to earlier onset of substance use and driving under the influence. Intimate partner violence increased women’s risks for property crimes, drug offending, and commercial sex work. Witnessing violence increased risks for property crimes, fighting, and use of weapons. Experiences of caregiver violence increased the risk of running away as a teen. Qualitative narratives were reviewed to provide insight into connections between women’s experiences and onset of criminal behavior. Findings demonstrate a need for gender-responsive and trauma-informed practices to address mental disorders and victimization among women offenders.