"A small change can make a huge difference": teachers' perceived roles, barriers, and strategies in tackling loneliness in schools.

Teachers, as key attachment adults in the school environment where children and adolescents spend substantial time, play a crucial supportive role in pupil's experiences of loneliness. This study captures teachers' perspectives on pupil loneliness through qualitative interviews with 16 primary and secondary school teachers (8 from England and 8 from China), covering pupils ages 6-18 years. Thematic analysis of those interviews uncovered four themes: Teachers as Key Attachment Figures in School Life, Teachers' Relational Work in Addressing the Social Dimensions of Loneliness, Professional and Institutional Barriers, and Teachers within a Multi-layered Attachment Ecology. Understanding teachers' perspectives helps to bridge the gap between research and practical application. The findings reveal various barriers that limit teachers' ability to alleviate pupil loneliness effectively; using socioecological model, we see those range from intrapersonal challenges, such as limited knowledge and reliance on rigid methods, to external factors like inadequate school resources and results-driven school policies. Despite those challenges, teachers wanted to support pupils who reported loneliness. Building on teachers' insights, we recommend addressing loneliness in schools by (1) integrating loneliness-specific interventions within a broader mental health framework, and (2) fostering a proactive, whole-school supportive climate. We outline a framework with four core elements-Knowledge Development, Social and Emotional Skills, Communication and Collaboration, and Observation and Adaptation-that should be incorporated into loneliness-focused teacher training programs. Including teachers from two countries allowed for a cross-cultural comparison of support strategies, underscoring the need for adaptable, universal frameworks and highlighting the importance of cultural sensitivity when developing interventions and sharing insights across cultural contexts.