The goal of this article is to reveal how through school theatre activities under authoritarian rule, changes took place in pupil knowledge, skills, attitudes, and behaviour regarding culture, namely, how the process of cultural learning occurs. I use a historical case study, specifically the case of the Valmiera School Theatre, which was the leading theatre group, not only in Soviet Latvia, but also in the entire Soviet Union. My primary sources are eight unstructured interviews, 20 published memoirs, articles in the press, theatre programmes, and photographs. One part of Soviet pedagogy was aesthetic upbringing, which was implemented through state-funded collectives, including school theatre groups. By participating in theatre activities, students gained knowledge of cultural heritage (literature, theatre, art, etc.), the ability to perform and acquire skills in other practical fields, and developed an appreciation of culture as a value. I argue that cultural learning through theatre was demonstrated by the fact that the students transferred their knowledge, skills, and attitudes to a new context, namely, their places of work and public cultural activities (e.g. amateur theatres). This case study also reveals the specific role of school theatre in the process of cultural learning, as well as some sensitive issues in the relationship between knowledge-orientated or formal educational environments, and the informal creativity of school theatre.