Childhood obesity prevention interventions have engaged coalitions in study design, implementation, and/or evaluation to improve research outcomes; yet, no systematic reviews have been conducted on this topic. This mixed methods review aims to characterize the processes and dynamics of coalition engagement in community-based childhood obesity prevention interventions. Data Sources: Studies extracted from Ovid MEDLINE, PubMed, and Web of Science; complementary original survey and interview data among researchers of included studies. Eligible Studies: Multisetting community-based obesity prevention interventions in high-income countries targeting children 0-12 years with anthropometric, behavioral, or environmental/policy outcomes. The Community-Based Participatory Research (CBPR) Conceptual Model was used as an overarching framework. Thirteen studies met inclusion criteria. Elements of CBPR were evident across all studies with community engagement in problem identification (n = 7), design/planning (n = 11), implementation (n = 12), evaluation (n = 4), dissemination (n = 2), and sustainability (n = 10) phases. Five studies reported favorable intervention effects on anthropometric (n = 4), behavioral (n = 1), and/or policy (n = 1) outcomes; descriptive associations suggested that these studies tended to engage community members in a greater number of research phases. Researchers involved in 7 of 13 included studies completed a survey and interview. Respondents recalled the importance of group facilitation, leadership, and shared understanding to multisector coalition work. Perceived coalition impacts included community capacity building and intervention sustainability. This review contributes to a deeper understanding of intervention processes and dynamics within communities engaged in childhood obesity prevention. Future research should more rigorously assess and report on coalition involvement to assess the influence of coalitions on multiple outcomes, including child weight status.