Based on an integrative model of emotional labor, the present study examined the relationships among teachers' emotional labor strategies, the emotional job demands of teaching, trust in colleagues and teacher efficacy. The results from a sample of 1115 Hong Kong primary school teachers showed that surface acting plays a dysfunctional role, but deep acting and expression of naturally felt emotion help to facilitate teacher efficacy. Meanwhile, trust in colleagues can be seen as an organizational resource for teachers, helping them to cope with the challenges brought by emotional job demands of teaching. Teachers are advised to perform emotional labor wisely.