Advance care planning honors patients' goals and preferences for future care by creating a plan for when illness or injury impedes the ability to think or communicate about health decisions. Fewer than 50% of severely or terminally ill patients have an advance directive in their medical record, and physicians are accurate only about 65% of the time when predicting patient preferences for intensive care. Decision aids can support the advance care planning process by providing a structured approach to informing patients about care options and prompting them to document and communicate their preferences. This review, commissioned as a technical brief by the Agency for Healthcare Research and Quality Effective Health Care Program, provides a broad overview of current use of and research related to decision aids for adult advance care planning. Using interviews of key informants and a search of the gray and published literature from January 1990 to May 2014, the authors found that many decision aids are widely available but are not assessed in the empirical literature. The 16 published studies testing decision aids as interventions for adult advance care planning found that most are proprietary or not publicly available. Some are constructed for the general population, whereas others address disease-specific conditions that have more predictable end-of-life scenarios and, therefore, more discrete choices. New decision aids should be designed that are responsive to diverse philosophical perspectives and flexible enough to change as patients gain experience with their personal illness courses. Future efforts should include further research, training of advance care planning facilitators, dissemination and access, and tapping potential opportunities in social media or other technologies.