Abstract: Participatory research can change the view of children from research subjects to active partners. As active partners, children can be recognized as agents who can contribute to different steps of the research process. However, “participatory research” is an umbrella term that covers both the collection of data with children and children’s participation in making decisions related to the research process. As such, it raises particular challenges for researchers. Based on a pragmatic ethics approach, we were inspired by the realist review methodology to synthesize the current literature, identify different strategies used to engage children aged 12 and below in participatory research, and analyze how they affect children’s active participation and the ethical aspects related to each. Fifty-seven articles were retained for inclusion in the review. A variety of strategies were used to involve children in the research process, including discussion groups, training/capacity-building sessions, photography and filming, children as data collectors and questionnaires. The most prevalent ethical considerations identified were related to power dynamics and strategies to facilitate children’s expression and foster the authenticity of children’s voices. Researchers should address these ethical considerations to actively involve children within the research process and prevent tokenistic participation. Active inclusion of children in research could include co-identifying with them how they want to be involved in knowledge production (if they want to) from the beginning of a project.