The current study examines how the perceived learning environment in teacher education contributes to the sense of professional agency in the classroom among first-year student teachers. The results revealed that the sense of professional agency in the classroom requires motivation to learn about teaching, efficacy beliefs about learning, and activities for facilitating and managing learning in the classroom. The results also demonstrate that these basic elements of professional agency were embedded in the contextualised components of student teachers’ sense of professional agency in the classroom. This study showed that the quality of peer relations is a key regulator for student teachers’ sense of professional agency from the very beginning of teacher studies. Peers are also shown to play a central role when facing challenges.