The mission of Adult Protective Services (APS) is to protect older and vulnerable adults from abuse, neglect, and exploitation. The complexity of APS cases and the potential for life-changing interventions point to the need for research that examines and evaluates APS practices. A literature review identified 50 studies published during a 16-year period that used APS agencies, clients, data, or resources to test hypotheses regarding elder abuse. The analysis revealed promising efforts toward knowledge development about elder mistreatment and self-neglect. This article provides an overview of salient findings, notes the scarcity of studies that analyze the effectiveness of APS, and highlights the need for additional research. Lessons learned are described, and APS practitioners and researchers are urged to work collaboratively to develop key practice-related questions about APS processes and outcomes that can be tested with appropriate research methodologies.