Policy advocacy is widely regarded as an eminent feature of nonprofit organizations’ activities, allowing them to represent their constituencies. The article presents a literature review of research on nonprofit policy advocacy that has been published over the last decade, focusing on advocacy by nonprofit human service organizations (NPHSOs) and its unique characteristics and contributions. The review focuses on several key topics, including: the definitions and origins of the term advocacy and its current uses in studies related to NPHSOs; the current situation and prevalence of NPHSO advocacy activities; organizational and structural variables as they relate to policy advocacy; dependence on external funding sources and policy advocacy; strategies, tactics, modes of operation, and the effectiveness of NPHSO policy advocacy. The article presents and discusses the implications of this research and suggests directions for future research.