The involvement of persons with disabilities in formal decision-making processes is thought to have a range of benefits. However, research suggests that participatory processes may fail to match normative ideals. This study examines the participation of persons with disabilities in the development of the United Nations Convention on the Rights of Persons with Disabilities, from the perspective of key informants in the New Zealand disability sector. It found that participants viewed the participatory process favourably. Political activity from persons with disabilities and political willingness on the part of government contributed to this perceived success. More broadly, the participation of persons with disabilities provided a mutually enriching learning experience, reduced political machinations between nations, increased government accountability, and resulted in a more relevant text. The study provides an example of a successful participatory process involving persons with disabilities within an international context.