The Patient Self-determination Act requires that health care institutions inform patients of their right to make health care preferences known through advance directives. However, actual advance directive documentation remains low. This study’s purpose is to identify and analyze research studies incorporating clinical decision support to improve rates of advance directive documentation. In addition, variables impacting advance directive documentation are identified. Literature searches were performed in the Cumulative Index of Nursing and Allied Health Literature, PubMed, and Scopus between 1998 and 2015. Search criteria yielded more than 2000 results using various search engines, yielding 34 articles with 35 studies total. Articles included 17 studies describing electronic health record–based decision support interventions for advance directive documentation (Supplemental Digital Content 1). In addition, 18 studies assessed factors influencing advance directive documentation (Supplemental Digital Content 2). Findings suggest that decision support–based reminders are effective in improving advance directive documentation. Use of e-mail reminders for patients before patient visits through electronic health record portals provides a mechanism to improve advance directive documentation rates. Furthermore, major factors influencing advance directive documentation include inconsistencies in end-of-life preferences between patients and providers and inconsistencies in patients’ preferences over time.