The international school sector in Hong Kong makes a substantial contribution to educational provision in the city, employing many expatriate teachers. Wellbeing has taken on increasing prominence in international school discourses, but little research has investigated how the wellbeing of international school teachers is influenced by school-level factors. For the purposes of this study, thirteen expatriate teachers from ten different international schools in Hong Kong were interviewed and the data were analysed thematically. The teachers' wellbeing was found to be influenced by relationships with students, colleagues and senior leaders, and a pervasive climate of accountability. Teachers felt a sense of social isolation associated with cultural differences, and often did not feel supported by their schools. Teachers' wellbeing, it is proposed, may be improved by the articulation of a shared vision which focuses on classroom-level interactions, an affiliative climate, and an institutional environment which addresses social isolation and protects teachers against an excessive climate of performativity and accountability.