Incarcerated women with co-occurring mental health and substance use disorders (COD) face complex psychosocial challenges at community reentry. This study used qualitative methods to evaluate the perspectives of 14 prison and aftercare providers about service delivery challenges and treatment needs of reentering women with COD. Providers viewed the needs of women prisoners with COD as distinct from those of women with substance use alone and from men with COD. Providers described optimal aftercare for women with COD as including contact with the same provider before and after release, access to services within 24-72 hours after release, assistance with managing multiple social service agencies, assistance with relationship issues, and long-term follow-up. Providers also described larger service system and societal issues, including systems integration and ways in which a lack of prison and community aftercare resources impacted quality of care and reentry outcomes. Practice and policy implications are provided.