The quality of family caregiver–patient interaction plays a crucial role in the context of chronic conditions. This study investigated the effects of a caregiver educational program on interactions between family caregivers and patients with advanced chronic obstructive pulmonary disease (COPD). In this trial, 92 pairs of family caregivers and patients in a subspecialty lung care clinic located in Birjand, Iran were allocated into intervention and control groups (n = 46 per group). The intervention consisted of eight sessions, including three educational sessions on COPD, two educational sessions on coping strategies, as well as three peer support sessions. The Dyadic Relationship Scale was completed at baseline, posttest, and follow-up (2 months after intervention). For caregivers in the intervention group, positive dyadic interaction improved significantly from baseline to follow-up and from posttest to follow-up in comparison with the control group (p < 0.05). Also, for these caregivers, negative dyadic strain enhanced significantly from baseline to posttest and from baseline to follow-up as compared with those in the control group (p < 0.05). Finally, in patients of the intervention group, negative dyadic strain from baseline to follow-up and from posttest to follow-up significantly improved when compared with that of control patients (p < 0.05).