Psychologists working in the public sector should, in addition to providing direct services, advocate for systems change. Although many consumers treated in the public sector face a constellation of severe life problems, working to improve the system of care is more difficult than providing treatment. Improving the quality of life of consumers of publicly funded mental health services requires that psychologists become advocates. Four prerequisites to systems change, plus coalition building, legislative advocacy, the work of state psychological associations, and forming alliances between psychologists and nonpsychological community organizations such as Rotary International, are described. In conclusion, 12 orienting ideas are listed for psychologists who want to advocate for social, institutional, and political change.