Child co-research has become popular in social research involving children. This is attributed to the emphasis on children’s rights and is seen as a way to promote children’s agency and voice. It is a way of putting into practice the philosophy, common amongst childhood researchers, that children are experts on childhood. In this article, we discuss ethical complexities of involving children as co-researchers, beginning with an analysis of the literature, then drawing on data from interviews with researchers who conduct child (...) co-research. We identify six ethical complexities, some of which are new findings which have not been mentioned before in this context. In light of these possible ethical complexities, a key finding is for researchers to be reflexive – to reflect on how the research may affect child co-researchers and participants before the research starts. A separate overriding message that came out in responses from the researchers we interviewed was the need for support and training for child co-... (shrink)