Implicit beliefs have received growing attention in the literature. However, past studies have usually focussed on students' implicit beliefs about intelligence. The present study aimed to extend the literature on implicit beliefs to the domain of teaching and examine whether implicit beliefs about one's teaching ability would predict teacher well-being. More specifically, this study investigated whether beliefs that teaching ability is fixed or malleable are associated with various well-being dimensions as indexed by positive emotions, engagement, positive relationships, meaning, and accomplishment. The participants were 547 in-service Filipino teachers who completed a survey assessing the study variables. Structural equation modelling was used to analyse the data. Findings revealed that holding a growth teaching mindset (i.e. that one's teaching ability can be developed and improved) positively predicted all the dimensions of well-being. The findings of the study highlight the importance of having a growth teaching mindset in the promotion of teachers' well-being.