Participation at the negotiation table for finding peace agreements can be conceptualized as a peacebuilding function of civil society. Studies which measure the impact of civil society’s participation at the negotiation table, however, are very scarce. Do people perceive inclusive peace treaties to be more legitimate? Does CSOs’ trustworthiness moderate the impact of inclusive peace treaties on people’s perception of the legitimacy of peace treaties? This study focuses on these questions by gathering and analysing data from 400 Turkish Cypriots. The survey experiment suggests that inclusiveness does not influence the perceived legitimacy of peace treaties. Moreover, the findings suggest a null effect with regard to CSOs’ trustworthiness and its multiplicative effect on perceived legitimacy based on civil society’s participation at the negotiation table.