Background: Social inclusion has been explored using a wide range of theories and methods. Belonging and reciprocity have been identified as key components of social inclusion. This systematic methodological review identifies and evaluates the theoretical frameworks and qualitative approaches adopted to explore belonging and reciprocity in the lives of adults with intellectual disabilities. Method: A systematic search was conducted across ten databases. Screening and quality appraisal were carried out independently by two researchers, and data were extracted to provide detailed accounts of the theories and methods employed. Results: Seventeen papers met inclusion criteria. Clear conceptualisations of belonging and reciprocity were lacking, and these concepts were rarely the focus of the research. Theoretical and methodological shortcomings across this literature were identified and discussed. Conclusions: More nuanced conceptualisations of belonging and reciprocity may be helpful in future research, to better capture the context and meaning of individual lives and relationships.