The choice to conduct research projects done with or by children is a political one. It reflects a standpoint that appreciates children's position as agentic beings and acknowledges their expertise. There are complex questions for academics and practitioners engaged in such research projects. This paper reports on a systematic review of peer-reviewed research relating to children as researchers. The scope of the analysis is limited to children aged 15 and under, who were involved in at least one component of a research project. Twenty-five published articles are included, and they demonstrate varied methods of engagement. The theoretical perspective the studies adopted may focus on one of three: (a) child-led research, (b) children as co-researchers, or (c) youth participatory action research. Not all studies included child researchers in all aspects of a research project, with participation influenced by the adopted theoretical perspective as well as reported barriers and challenges. This review presents the results of a systematic examination of the included papers, including approaches and methodological considerations as well as the socio-cultural contexts within which projects are carried out. We discuss situational tensions that might inhibit the capacity of adults and children to partner in co-creating new knowledge and developing robust ways of working together. Finally, we draw attention to three significant dimensions within the findings: the influence on the children-as-researchers paradigm of hierarchical structures inherent to academic institutions; the importance of engaging with specific historical, political, and social contexts; and challenges for inclusion and diversity.