A central goal of group-based psychotherapy is for participants to gain insight into how they perceive others and how others perceive them. However, such interpersonal perceptions are challenging to study because any given perception could be a function of the perceiver (some people see everyone as friendly), the target (some people are seen as friendly by everyone), or both. The present article provides an introduction and brief tutorial for how the social relations model (SRM) can be applied to studying such interpersonal perceptions within psychotherapy groups. The SRM is a theoretical and statistical model for understanding the possible sources of dyadic perceptions and behaviors. Specifically, any interpersonal perception within a group can be partitioned into variance due to the person making the rating (perceiver effect), the target of the rating (target effect), the relationship between perceiver and target (relationship effect), and the group as a whole. Research on group psychotherapy is especially amenable to a SRM analysis because the interpersonal context allows multiple perceivers to rate multiple targets, which is a requirement of any SRM analysis. A fictitious study of wilderness therapy is used to highlight the conceptual, methodological, and statistical issues that are addressed with the SRM. Supplementary data and output files are provided to elucidate the analytic process using the WinSoReMo software. Although there are multiple ways that SRM studies and analyses can be conducted, the WinSoReMo program is specifically designed for round-robin data in which group members rate, and are rated by, other group members.