Research on mindsets have mostly focused on students’ beliefs about the malleability of their intelligence. However, past studies have not explored how teachers’ beliefs about the malleability of their teaching ability is associated with teaching emotions and work engagement. Akin to intelligence mindsets, teachers might also hold either a fixed or growth mindset towards their teaching ability. We tested a model wherein teachers’ emotions (i.e., enjoyment, anger, and anxiety) mediated the relationship between mindsets about teaching ability and engagement. A total of 547 teachers (M = 39, SD = 8.63 years; 89.6% female) completed questionnaires on mindsets about teaching ability, emotions, and work engagement. Results showed that holding a growth mindset about one’s teaching ability positively predicted enjoyment, which in turn, predicted engagement. Theoretical and practical implications are discussed.