Introduction: The World Health Organization has reported that one fifth of all children in the world suffer from poor mental health regardless of cultural differences. Previous studies have shown that working with mental health is an important part of the duties of school nurses in Sweden.

Objective: The aim of the present study was to describe the experiences of school nurses regarding the identification of mental illness among pupils in primary school.

Methods: In this inductive qualitative study, interviews were conducted with 11 school nurses in southern Sweden and analyzed using content analysis.

Results: The results indicate three major themes: (1) the need for shared responsibility, (2) feelings of uncertainty and inadequacy in school nurses, and (3) the importance of establishing relationships.

Conclusion: This study indicates that school nurses feel responsible for their pupils' well-being, but also feel that they need support. A lack of guidance in identifying mental illness emerged from the interviews.