Wellbeing is crucial for teachers, not only for themselves but also for ensuring that they teach to the best of their abilities. Thus, identifying ways of empowering teachers to take action to boost or maintain their wellbeing is vital. In this article, an ecological lens is adopted to understand what determines language teachers' agency for wellbeing. A thematic analysis of in-depth interviews with 30 EFL teachers based in Austria revealed four key themes which help to explain how teachers exercise their agency for wellbeing. These are: triggers, reflection, affordances, and action. The results show that critical incidents in their personal and professional domains act as triggers drawing teachers' attention towards their wellbeing and starting a process of deeper reflection. However, a prerequisite for taking action following this reflection appears to be a perceived sense of control about their ability to change things in their personal and professional lives.