IntroductionAdolescents with obesity are more likely to be isolated by peers, but whether they also choose to disengage from their peers remains unclear.MethodsThis study examined a sample of 646 adolescents between the age of 13 and 16 across 34 classrooms in 3 junior high schools in Taiwan, with data collected from May to June 2019. The sociometric network nomination method assessed peer relationships, such as unpopularity, unsociability, and alienation. Multilevel models were applied to explore the extent to which the class‐level prevalence of overweight and obesity and peer support moderate the relationship between student‐level obesity and peer relationships.ResultsOverall, students with obesity were more likely to experience unpopularity, unsociability, and alienation from their peers in classroom settings (adjusted odds ratio [AOR] = 1.904, 2.208, 2.777, p < .05). Regardless of their obesity status, students in high classroom peer support were less likely to report unsociability (AOR = 0.124, p < .05). No cross‐level interactions were observed, indicating that students with obesity did not experience a reduction of peer rejection in high peer support classrooms. Neither did obese students in classrooms with higher rates of overweight and obesity.ConclusionsStudents with obesity were more likely to experience interpersonal problems. Classroom peer support can increase peer acceptance for typical students but has no beneficial influence on adolescents with weight problems. Classroom peer support needs to be directed to become adequate support for students with obesity.