This study aims to examine the mediating effect of teacher self-efficacy on the relationship between collective efficacy and organizational citizenship behaviour among teachers from public secondary schools. A total of 232 valid samples were collected. Partial least square approach was adopted to conduct a comprehensive structural equation modelling. Findings revealed that teacher's self-efficacy and its dimensions: personal teaching efficacy and general teaching efficacy are statistically significant to organizational citizenship behaviour. Additionally, collective efficacy is insignificantly related to organizational citizenship behaviour, but it must influence organizational citizenship behaviour indirectly through teacher's self-efficacy and its dimensions: personal teaching efficacy and general teaching efficacy. Several implications are discussed theoretically and practically.