The ongoing opioid crisis in Canada has led to the establishment of supervised consumption sites (SCSs) as a key harm reduction strategy. The benefits of SCSs for people who use drugs (PWUD) and their experiences with stigma are well documented. However, less attention has been given to the stigma experienced by Registered Nurses (RNs) working in these settings. Addressing this critical gap, through the lens of stigma theory (Goffman, 1963) using the methodology Interpretive Phenomenological Analysis (IPA), this study explores the experience of courtesy stigma using semi-structured interviews with five SCS RNs in a Canadian context. This phenomenon of courtesy stigma results from SCS RNs’ close associations with their stigmatized SCS clients. Five overarching themes emerged from this study: 1) Deer in the Headlights: The Mystery of the SCS RN Role; 2) Slap in the Face: Consequences of Courtesy Stigma for SCS RNs; 3) Poking the bear: SCS RNs Predicting Negative Reactions; 4) The Uphill Battle: Resisting Courtesy Stigma for SCS RNs; and 5) Fighting Back: Advocacy and Social Justice in SCS RN Nursing. Study findings revealed that courtesy stigma manifested misconceptions about their SCS RN role, affecting the nurses’ social relationships, disclosure practices, and professional identity. Nevertheless, participants responded with resilience, and courtesy stigma enhanced their commitment to harm reduction advocacy and social justice. These results underscore the need for increased public awareness, institutional support, and policy initiatives that address courtesy stigma toward healthcare professionals in harm reduction settings, especially in the advent of the opioid crisis.