Evaluators widely agree that stakeholder involvement is a central aspect of effective program evaluation. With the exception of articles on collaborative evaluation approaches, however, a systematic review of the breadth and depth of the literature on stakeholder involvement has not been published. In this study, we examine peer-reviewed empirical studies as the first step in establishing a firm foundation for a discussion of stakeholder involvement. We excluded all studies that did not provide descriptions of their methods, helping ensure that we only reviewed studies with strong methodological warrants for their findings. We address three key questions about the state of the empirical literature on stakeholder involvement, focusing on the studies' methodological and contextual characteristics, and the involvement themes and substantive nature (positive, negative/mixed, or explanatory/normative) of the findings. We provide detailed findings in an appendix at http://aje.sagepub.com/supplemental or http://goo.gl/W8oMnl.