This chapter discusses participatory action research (PAR) as an EDI research strategy, directed at improving the situation of less powerful groups by encouraging these groups to participate in the research process and thus to acquire knowledge, learn and emancipate in support of their inclusion in society. The authors describe three examples of PAR in different fields of diversity, showing different levels of ‘insider participation’ of researchers. The first is a case study on part-time workers in the Netherlands, where focus group interviews were used to involve part-time workers in analyzing hindrances and enablers in their careers. The second is an ethnographic field study, where the homecoming experience of African Americans in Ghana was examined by performing participant observation, actively involving insiders in this situation. The third is an intervention study aimed at supporting gender equality in academia, where group model building was used to involve all stakeholders, in understanding and addressing gender inequality in science.