Aims: The way people who inject drugs (PWID) feel about drug policy may be profoundly shaped by lived experience of stigma and the subjectivities made available in policy and practice. Using a community-based participatory research approach, this study investigated why PWID hold particular views, and considered the complexities of how lived experience and opinions about drug policy intersect within this affected community. Methods: Three qualitative focus groups were undertaken. Participants were presented with survey results arising from a previous study, and asked to interpret and explain the possible rationales underlying the opinions expressed by their peers. Findings: A duality of opinion was identified, borne from lived experience of stigmatisation, which sometimes led PWID to qualify levels of support. By exploring the rationales underlying opinions, a tension emerged between what PWID theoretically know to be effective interventions, and experiences of how policies are delivered. A sense of "within-group" stigma emerged, with sub-groups of users and drug types denoted as more "dangerous" than others. Conclusions: This study illustrates how theoretical knowledge and lived experience intersect to inform opinions about drug policy. Through in-depth discussions with the affected community, we are reminded that public opinion research is always an interpretative and sensitive pursuit.