Engaging students in authentic scientific research has become an important component of undergraduate science education at many institutions. The purpose of this paper is to explore authentic research experiences as contexts for learning. The authors review empirical studies of undergraduate research experiences in order to critically evaluate the outcomes of these efforts. The review is organized around learning outcomes including career aspirations, confidence, nature of science, intellectual development, content knowledge, and skills. The research indicates that undergraduates tend to demonstrate gains in these areas, but the extent to which these gains match expected and possible gains varies across outcomes. This analysis suggests that program coordinators and research mentors should consider length of experiences, engagement of students in epistemically demanding practices, and incorporation of explicit instructional supports.