We explore the relationship between overweight and adolescents' academic performance and other nonacademic outputs, such as life satisfaction and health status, body image, friendships, sense of belonging to school, being bullied and attitudes towards bullying. For this purpose, we employ data on 15-year-old students from PISA 2018 for nine countries, using regression discontinuity analysis around the body mass index overweight cut-off. Our results show that overweight students do not seem to perform differently compared with normal-weight students, but may be less satisfied with life and their health status, have a poorer body image and a higher likelihood of suffering social isolation and being bullied. Regarding students' sense of belonging to school, results are quite mixed and depend on the country. Surprisingly, overweight students seem to be less empathic with students who suffer from bullying than normal-weight students, even though they are more likely to be bullied themselves.