BACKGROUND: Peer assistance is an emerging area of study in injection drug use. When Canada's first supervised consumption site (SCS) opened in 2003 in Vancouver, Canada, clients were prohibited from injecting their peers; only recently has this practise been introduced as a harm reduction measure at these sites. In 2018, Health Canada granted federal exemption to allow peer-assisted injection at certain SCS sites, under the Controlled Drugs and Substances Act. Literature pertaining to peer-assisted injection addresses several topics: interpersonal relationships between the injection provider and recipient; the role of pragmatism; trust and expertise; and gender relations. METHODS: In this qualitative study, participants (n = 16) were recruited to be interviewed about their experiences in a peer-assisted injection program (PAIP) at one SCS regulated by Health Canada. Interview data were transcribed and thematically analyzed. Quantitative administrative data were used to provide context and to describe the study population, comprised of people in the PAIP (n = 248). RESULTS: PAIP clients made up 17.4% of all SCS clients. PAIP clients were more likely to be female and Indigenous. Injection providers expressed being moved by compassion to help others inject. While their desire to assist was pragmatic, they felt a significant burden of responsibility for the outcomes. Other prominent factors related to the injection provider-recipient relationship were social connection, trust, safety, social capital, and reciprocity. Participants also made suggestions for improving the PAIP which included adding more inhalation rooms so that if someone was unable to inject they could smoke in a safe place instead. Additionally, being required by law to divide drugs outside of the SCS, prior to preparing and using in the site, created unsafe conditions for clients. CONCLUSIONS: Regular use of the SCS, and access to its resources, enabled participants to lower their risk through smoking and to practice lower-risk injections. At the federal level, there is considerable room to advocate for allowing clients to divide drugs safely within the SCS, and to increase capacity for safer alternatives such as inhalation.