Participatory guarantee systems (PGS) have become increasingly important for organic quality assurance. PGS are promoted as more suitable than third-party certification (TPC) for smallholder farmers in the Global South. The advocated benefits of PGS include the promotion of organic agriculture, farmer empowerment, and the facilitation of food system sustainability. To deliver these benefits, local actor participation is key. To date, there is still an absence of in-depth studies on participation in PGS in the literature. The aim of this study was to contribute to closing this research gap by (i) conducting a meta-analysis on PGS participation and (ii) presenting a framework for studying actor participation in PGS. A systematic literature review on participation in PGS was carried out, using a framework based on Cohen and Uphoff (1980). The results showed that data on participation in PGS are still fragmented in scientific literature. Quantitative empirical evidence and data on the extent and purpose of participation and actors’ perception of participation, for example, are very scarce or not available at all. This paper argues that a systematic and theory-based approach to further research on participation in PGS is needed for improved understanding and facilitation, and suggests an adapted version of Cohen and Uphoff’s (1980) framework for conducting this research.