Childhood obesity is a significant public health challenge, yet research priorities for childhood obesity prevention are not established. Coproduction of priorities leads to research which may be more translatable to the domains of policy and practice. The aim of the present study was to identify knowledge gaps and research priorities in addition to facilitators and barriers to knowledge translation in childhood obesity prevention. The nominal group technique involving consensus building with researchers, policymakers, and practitioners was employed during workshops at a national obesity conference held over 2 days in May 2017. Seventy-seven people participated in the first round of research prioritization on Day 1, while 14 stakeholders participated on Day 2. The top five research priorities identified were as follows: (i) Evaluate (including economic evaluation) current programs to inform practice and policy; (ii) How to change culture toward addressing the determinants of health; (iii) Implementation science: process; (iv) How to integrate obesity prevention into existing service structures; (v) How to enhance opportunities for habitual physical activity, including free play and active travel. Key themes emerging from this research prioritization exercise were the importance of funding and resources, coproduction of research, and a focus on both implementation research and social determinants within the field of childhood obesity prevention. The coproduced research priorities may help to shape the research agendas of funders and researchers, and aid in the conduct of policy-relevant research and the translation of research into practice in childhood obesity prevention.