Community participation is a foundational principle of primary health care, with widely reputed benefits including improved health outcomes, equity, service access, relevance, acceptability, quality and responsiveness. Despite considerable rhetoric surrounding community participation, evidence of the tangible impact of community participation is unclear. A comprehensive literature review was conducted to locate and evaluate evidence of the impact of community participation in primary health care on health outcomes. The findings reveal a small but substantial body of evidence that community participation is associated with improved health outcomes. There is a limited body of evidence that community participation is associated with intermediate outcomes such as service access, utilisation, quality and responsiveness that ultimately contribute to health outcomes. Policy makers should strengthen policy and funding support for participatory mechanisms in primary health care, an important component of which is ongoing support for Aboriginal Community Controlled Health Services as exemplars of community participation in Australia. Primary health-care organisations and service providers are encouraged to consider participatory mechanisms where participation is an engaged and developmental process and people are actively involved in determining priorities and implementing solutions.