Emotions and identities are at the core of all human activity and learning. Emotions motivate us, help us to make sense of our experiences and teach us about ourselves, in other words shape our identities. Emotions are thus in a key role in planning and developing language teaching at schools. This article focuses on the role of emotions and identities in learning and teaching a language. The article shows how different emotions affect language learning and the identity development processes of the learner, and how language teachers can help their students to deal with their emotions and turn them as a resource for identity development. We also look at the meaning of emotions and teacher identities in language teacher development.