Peer Relationship Difficulties in Multiethnic Classrooms: A Longitudinal Study

Peer relationship difficulties during adolescence can significantly affect development. As classrooms become increasingly multiethnic, little is known about how native students navigate these contexts, while research on students with an immigrant background has mainly examined the onset of peer relationship difficulties. Moreover, the impact of the classroom ethnic composition-the proportion of students with an immigrant background relative to native students-remains unclear, with various theories offering conflicting perspectives. To address these gaps, this study examines the longitudinal development of peer relationship difficulties, considering students' immigrant backgrounds and classroom ethnic composition. Two data collections were conducted (T1: December 2021/January 2022; T2: May/June 2022) in Italy. The sample included 604 first-year high school students (M_age = 15.16; SD_age = 0.56; 17.5% with an immigrant background; 52.9% males) nested within 30 classrooms across 8 schools. Results from the random intercept linear mixed model showed an increase in peer relationship difficulties for native students in medium and highly multiethnic classrooms, where the proportion of students with an immigrant background was above the sample mean, but not in low multiethnic classrooms (below the sample mean). Students with an immigrant background experienced an increase in peer relationship difficulties over time across all classroom conditions. Classroom ethnic composition plays a crucial role in shaping peer relationship difficulties, suggesting that the presence of multiple ethnic groups may present additional challenges. The study underscores the need for targeted, inclusive interventions and contributes to theoretical debates on the social dynamics of multiethnic classrooms.