Introduction and Aims: Although loneliness is common among people with substance use disorders, few interventions to reduce loneliness have been developed for this population. This study aimed to determine the feasibility of delivering a six-session group-based intervention, ‘Groups for Belonging’, that builds social group connectedness. Design and Methods: Participants were 41 individuals accessing residential substance use treatment services. The primary aims of the present study were to determine indicators of feasibility of Groups for Belonging; namely, demand (recruitment, attendance and retention) for and acceptability (program adherence and participant satisfaction) of the Groups for Belonging program in residential substance use treatment settings. Results: Over half of the people attending the services were interested in participating in Groups for Belonging. Of 41 participants who commenced the program, 20 participants completed the program per protocol. In terms of acceptability, the average number of sessions attended was 3.7 (SD = 1.76, range 1–6). Program adherence was 99.3% and overall satisfaction with the program was high, with 95% of participants reporting they enjoyed Groups for Belonging. Discussion and Conclusions: The Groups for Belonging program may be feasible for delivery in residential substance use treatment services. Findings from this study suggest that an adequately powered replication study is warranted.