This study investigated the agency of children, parents and teachers in a Serbian-English bilingual preschool. The focus was on uncovering the kind of agency each of these groups exercised in the process of language learning by examining the children's linguistic behaviour and the role that parents and teachers had in motivating children learning English as a foreign language. The results show that, within a model which relied on strict separation of languages, the children initiated communication with their L2 teacher mostly in their L1. Even when they faced a question in L2, the children answered both in L1 and L2, which shows the need for a different approach in teaching. On the other hand, the lack of teachers' and parents' agency in providing adaptations to the teaching model and promoting flexibility in the teaching process has been found to be caused by the strictly predefined applied model, with little room for modification. Thus, the needs of the learners could not be served fully, although both the teachers and the majority of parents used any opportunity to influence the language learning process by encouraging the children to learn a second language and by shaping their attitudes toward it.