This chapter analyzes the relationship between adolescent mental health and the effects of the COVID-19 pandemic on youth sociability. The focus is on three spheres of sociability: peer interaction, family life, and urban experience. The main findings show the relevance of face-to-face sociability in this period of life, and how its disruption had a significant effect on the socioemotional well-being of young people. Mexico has been one of the countries with the longest school closure in the world (almost 2 years) which has dealt a critical blow to youth social life. The analysis is based on information from a Youth Participatory Action Research (YPAR) on adolescence and the COVID-19 Pandemic that privileged the voices, emotions, and perceptions of the participants, applying innovative qualitative techniques. Students from an upper-middle school located in the popular outskirts of Mexico City were invited to participate as co-researchers and thus, to co-create a research process driven by their lived experiences of the pandemic. In total, 61 students (41% male and 59% girls) from 17 to 19 years old were involved. Fieldwork was carried out between October 2020 and August 2021.