The Role of Supportive Teacher Student Relationships for Social Participation in Ethnically Diverse Classrooms Authors: Carmen Barth (carmen.barth@uni-konstanz.de), Vera Paukstat, & Jeanine Grütter, University of Konstanz As ethnic diversity in schools is increasing, it is important to understand how positive contacts between students from the host country and students with a migration background can be facilitated. This knowledge is important, as recent research shows that students with a migration background face a higher risk for being excluded or bullied by peers (e.g., OECD, 2018). The current contribution draws from a peer ecology approach (e.g., Farme et al., 2019) and examines whether teachers who manage to build supportive relationships with their students can positively shape classroom dynamics and social participation. Based on two studies with samples from Germany (Ntotal = 1299, Nmigrant background = 363, 4th graders) and Switzerland (Ntotal = 1018, Nmigrant background = 384, Mage = 11.18 years), we analyzed students’ peer nominations (i.e., Switzerland: “Which children in your class are popular?”, “Which children in your class are your friends?”) or peer ratings (i.e., “How much would you like to sit next to this student?”). In both studies, students’ perceptions of their class teachers’ emotional support were assessed (e.g., “The teacher cares about me.”, “The teacher helps me if I have trouble with other students from my classroom.“, adapted from Ryzin et al., 2009). In both studies, students with a migration background were, on average, evaluated more negatively by peers than students without migration background. The results (based on multilevel analyses) from the German sample highlighted the potential of supportive student-teacher relationships to promote more positive evaluations interethnic peer relations (i.e., more openness to sit next to students from either ethnic minority or majority groups) in ethnically diverse classrooms. Similarly, the results from the multilevel models based on the Swiss sample showed that, at the level of the classroom, high perceived emotional support by the teacher was associated with a greater number of friends. However, at the individual level, high perceived emotional support by the teacher was surprisingly associated with significantly less popularity for students with a migrant background compared to students without such. Taken together, emotionally supportive student-teacher relations can foster openness for interethnic dyads and friendships among students. However, at the same time, teachers may need to reflect on the perceived balance of providing support to students as their support may – under certain conditions - contribute to a difference in popularity to the disadvantage of students with a migrant background. A promising avenue for future research may be to conceptualize the role of emotional teacher support as an important social resource and investigate students’ perceptions of fairness. Key words: teacher-student relationship, emotional support, ethnic minority groups students, popularity, friendship, social participation