Posttraumatic stress disorder (PTSD) remains largely untreated among adults with severe mental illnesses (SMI). The treatment of psychotic symptoms usually takes precedence in the care of adults with SMI. Such oversight is problematic in that PTSD in SMI populations is common (19%-43%), contributes a significant illness burden, and hinders mental health care. Yet few public-sector mental health agencies routinely provide specialized services for PTSD. The purpose of the article is to describe strategies and efforts to disseminate trauma-focused empirically based practices in a public-sector mental health system. Identified challenges include limited resources and commitment; knowledge deficits, attitudes, and biases; and limited practice accountability at provider, facility, and system levels. Proposed strategies for overcoming these challenges are to set clear goals, nurture broad-based organizational commitment and key stakeholder involvement, implement specialty training efforts to provide information and change attitudes, provide ongoing supervision, conduct fidelity monitoring, and ensure accountability to the extent possible.