Recently, attachment-informed researchers and clinicians have begun to show that attachment theory offers a useful framework for exploring group psychotherapy. However, it remains unclear whether patients with differing attachment classifications would behave and speak in distinct ways in group therapy sessions. In this study, we conducted an exploratory analysis of the discourse of patients in group therapy who had independently received different classifications with gold standard interview measures of attachment in adults. Each patient participant attended one of three mentalization-based parenting groups. Before treatment, the Adult Attachment Interview (AAI) or the Parent Development Interview (PDI) were administered to each patient, and interviews were transcribed and coded to obtain the patient's attachment classification. Groups included 2, 5, and 5 patients, respectively, and any session was led by at least two co-therapists. A total of 14 group sessions were transcribed verbatim. Sessions were analysed through a semi-inductive method, in order to identify markers that would typify patients of different attachment classifications in session. Through transcript excerpts and narrative descriptions, we report on the differing ways in which patients of different attachment classifications communicate in group psychotherapy, with the therapist and with each other. Our work provides useful information for group therapists and researchers regarding how differences in attachment status may play out in group sessions.