The health emergency generated by COVID-19 and the massive closure of schools has given rise to an unprecedented situation for education systems worldwide. This situation has raised fundamental questions about the role of the school in contemporary societies and whether it still fulfils a particular function as a social institution. This article forwards a theoretical discussion on these issues from a critical sociological approach and, especially, from the perspective of social justice. It argues that the two main functions of schools, namely, socialisation and selection, cannot be fully achieved by distance schooling. Moreover, it contends that the lockdown of schools reinforced the crisis of meaning within the school system by hindering its ability to ensure learning for all students. Overall, the article presents a reflection on the meaning of the school institution in the 21st century, representing a key contribution to contemporary debates on the sociology of education.