The Affordable Care Act (ACA) includes provisions to shift the U.S. health care system to address achieving wellness rather than just treating illness. In this Open Forum, the Prevention Committee of the Group for the Advancement of Psychiatry describes opportunities created by the ACA for improving prevention of mental illnesses and promotion of mental health. These include improved coverage of preventive services, models to integrate primary and behavioral health care, and establishment of the National Prevention, Health Promotion, and Public Health Council, which has developed a National Prevention Strategy. The authors describe the important role that psychiatrists can play in advancing prevention of mental illnesses, in particular by working to incorporate prevention strategies in integrated care initiatives and by collaborating with primary care providers to screen for risk factors and promote mental and emotional well-being.