Ambiguities and tensions can arise when children are facilitated to act as ‘primary researchers’ concerning whether this is primarily to support their ‘participation’ in knowledge production and, with the knowledge produced, in relevant decision-making processes or whether it is mainly for any educational benefits. This article considers these ambiguities and tensions theoretically and by using evidence from a study where English primary school children were supported to conduct their own research projects. It concludes that, while the boundaries between children’s research as participation and pedagogy can be ambiguous, it should not be promoted for its potential educational benefits alone.