The field of participatory research with children developed largely thanks to shared learning between different cultures, places, and disciplines. However, grand narratives and power relationships in academia inherited from colonialism and imperialism can threaten to obstruct the transformative value of this approach. In this article, we present the case of Think Big, a multinational collaboration for participatory research with children that involved adult and child coresearchers from Australia, Chile, Colombia, and the United Kingdom. Our aim was to explore how this project helped build solidarities between adult researchers from different countries and disciplines. We applied a methodology of diffraction to explore the processes and outcomes of this collaboration and presented our insights using the metaphor of a tree to explain the roots (knowledges and frameworks), trunk (ongoing collaboration and communication between the teams from different countries), branches (local projects), and fruits (research outcomes) of our work. Based on our experience, we proposed that multinational collaborations for participatory research offer important opportunities for adult researchers to collaborate with children to generate more democratic knowledge about their lives and to generate more egalitarian relationships between adult researchers from different places and backgrounds. However, it is important to anticipate that multinational collaborations are more likely to be affected by social and political upheavals, and language barriers must be overcome to decentralize academia. Also, the organizations involved in these collaborations need to develop strategies that facilitate funding, ethics clearance, and international research agreements.