Useful lessons can be drawn from realist evaluation and appreciative inquiry for the evaluation of tourism interventions in complex contexts. We combine the strengths of these two approaches to design a participatory learning-focused evaluation with an emphasis on co-created intervention improvement. We apply this proposed ‘Realist Appreciative Evaluation’ on a government-led intervention aimed at supporting tourism firms to improve their sustainability practices. While realist evaluation introduces causal thinking within a framework of contexts-mechanisms-outcomes, appreciative inquiry enables participants to be solution-oriented. The study shows how evaluation can constitute a constructive, dynamic learning process for participants, rather than something to fear. Our methodology promotes collaboration and real-time change, within the rigorous theory-based realist evaluation approach, to improve the evaluation of tourism interventions.