Aim To investigate the effects of wearing masks in terms of well-being, behavior and psychosocial development on children and adolescents during the COVID-19 pandemic. Methods Expert interviews were conducted with educators (n=2), teachers from primary and secondary education (n=9), adolescent student representatives (n=5) as well as paediatricians from primary care (n=3) and the public health service (n=1), transcribed and subjected to thematic analysis using MAXQDA 2020. Results The most frequently reported short- and medium-term direct effects of mask-wearing were primarily in terms of limited communication due to a reduction in hearing and facial expressions. These restrictions in communication had consequences for social interaction and teaching quality. It is assumed that there will be effects on language development and social-emotional development in the future. A reported increase in psychosomatic complaints as well as anxiety, depression and eating disorders was attributed more to the conglomerate of distancing interventions than to just wearing of masks. Vulnerable groups were children with developmental difficulties, those with German as a foreign language, younger children, and shy and quiet children and adolescents. Conclusion While the consequences of mask-wearing for children and adolescents can be described quite well for different aspects of communication and interaction, effects on aspects of psychosocial development cannot be clearly identified yet. Recommendations are made primarily for dealing with the limitations in the school setting.