Social support is a feature of instructional behaviour, it is an engaged behaviour of enthusiastic teachers. As an altruistic behaviour, teachers’ social support to students has been regarded as a factor that impact teachers’ well-being, however, this factor has yet to explore. The present study attempts to fill such research gap. The paper first reports a survey study based on 309 Hong Kong teachers. The path analysis results showed that Psychological Need Satisfaction at Work (BPNW) significantly predicts the three indicators of well-being, i.e. Psychological Meaningfulness, Health and Work Engagement. The predictive patterns of BPNW on well-being are mostly consistent. The results also suggested that the mediating effects of social support between BPNW and well-being indicators are small. Given the positive correlations with both BPNW and well-being indicators, social support can be regarded as an instructional behaviour that would benefit teacher development. The second part of the paper reports interviews of a sample of 15 teachers. Content analysis suggests that teachers’ source of satisfaction has largely derived from engaging with students, such as in assisting students’ growth, or developing good teacher-student relationships; teacher satisfaction derives from higher-order value of a job (i.e. serving students) that causes psychological meaningfulness and commitment. Implications to the development of enhancement programs promoting BPNW to boost teachers’ wellbeing and engaging teaching behaviour will be discussed. The study highlights eudemonia satisfaction as the core of well-being, for teachers, social support behaviour may be significant indicator of work engagement. Copyright © 2022 Tenth SELF International Conference.