--- - |2+ Background Co‐research with people with intellectual disability is a distinct form of patient and public involvement (PPI). This systematic review summarize published studies and protocols to report on the process of co‐research in social and healthcare research. Method Relevant studies were identified using electronic searches on ASSIA, PsycInfo and MedLine. Study quality was assessed, and information relevant to the process of working with co‐researchers was extracted and thematically analysed. Results Thirteen studies were retrieved. Data are reported under three themes: (i) challenges of co‐research; (ii) facilitators of co‐research; (iii) benefits of co‐research. Best practice is presented as a model of co‐research. Content analysis on 12 research protocols identified four themes related to PPI. Conclusions All stakeholders involved in co‐research with people with intellectual disability can benefit, providing there is adequate infrastructure to accommodate and empower the co‐researchers. Many current intellectual disability research projects still lack systematic involvement of PPI members. - Journal of Applied Research in Intellectual Disabilities, Volume 31, Issue 5, Page 669-686, September 2018.