Introduction and Aims The dramatic increase in pharmaceutical opioid (PO) use in high‐income countries is a growing public health concern. Stigma and social support are important as they may influence treatment uptake and outcomes, yet few studies exist regarding perceived stigma and social support among people with PO dependence. The aims of the study are to: (i) compare characteristics of those with PO dependence from iatrogenic and non‐iatrogenic causes; (ii) document perceived stigma and its correlates in people in treatment for PO dependence; and (iii) examine correlates of social support in people in treatment for PO dependence. Design and Methods This prospective cohort study included (n = 108) PO‐dependent people referred from treatment services. Telephone interviews were conducted at baseline, 3, 12 and 24 months. Multivariate linear regression was used to examine correlations. Results Mean age was 41 (SD = 10.5). Half (n = 56, 52%) were female. Two in five met the criteria for iatrogenic dependence (n = 41, 38%), with iatrogenic dependence associated with chronic pain, and no history of injection or heroin use. One quarter of study subjects reported past month unsanctioned opioid use (n = 25, 23%). Being married/de facto or female was associated with higher levels of perceived stigma. Unsanctioned opioid use, iatrogenic dependence and mental health conditions were associated with lower social support. Discussion and Conclusions Stigma affects all people in treatment. Those who are married/de facto and female may benefit from interventions to address stigma. The association of low social support with poorer mental health and ongoing substance use indicate that treatment could focus more on this area.