This Emerging Evidence Report shares evidence of how, for whom, and under what circumstances, Participatory Action Research (PAR) leads to innovative actions. A rapid realist review was undertaken to develop programme theories that explain how PAR generates innovation. The methodology included peer-reviewed and grey literature and moments of engagement with programme staff, such that their input supported the development and refinement of three resulting initial programme theories (IPTs) that we present in this report. Across all three IPTs, safe relational space, group facilitation, and the abilities of facilitators, are essential context and intervention components through which PAR can generate innovation. Implications from the three IPTs for evaluation design of the CLARISSA programme are identified and discussed. The report finishes with opportunities for the CLARISSA programme to start building an evidence base of how PAR works as an intervention modality, such as evidencing group-level conscientisation, the influence of intersecting inequalities, and influence of diverse perspectives coming together in a PAR process.Foreign, Commonwealth & Development Office