Background: Celiac disease requires appropriate management and support, both medically and psychologically. This is especially important for adolescents, who may benefit from relevant peer interactions. Objective: This study evaluated the effects of interactive peer support on quality of life, friendship relations, and coping levels among adolescents with celiac disease. Method: This was a randomized controlled trial in which 36 adolescents (13–18 years of age) with celiac disease were equally divided into study and control groups. The study group was exposed to six interactive peer group sessions that were held every other week for 3 months under the supervision of nurses, while the control group was not exposed to any sessions, training, or consulting. All were assessed at baseline and post-intervention via the Pediatric Quality of Life Inventory, Friendship Qualities Scale, and KIDCOPE scale. Results: Several changes were detected upon final assessment. First, the mean scores for the PedsQL and FSS were significantly higher in the study group when compared to the control group. Second, the study group had higher mean scores for active coping and avoidance coping when compared to baseline. Third, the study group had significantly lower mean scores for negative coping when compared to the control group. Conclusions: Under the supervision of nurses, participants who were exposed to the peer support group showed improved quality of life, decreased social isolation, and enhanced positive coping strategies when dealing with celiac disease. ClinicalTrials.gov Identifier NCT04533776.