Background: Education Outside the Classroom (EOtC) is a teaching method that is gaining traction, aiming to promote learning and well‐being. However, research on the association between EOtC and well‐being is limited.

Methods: This quasi‐experimental trial involved pupils (9–13 years) from 16 Danish public schools which implemented EOtC in some classes. Pupils (N = 511) from 27 classes were regularly exposed to EOtC (2–7 hours per week), and pupils (N = 120) from 7 parallel comparison classes were much less exposed (less than 2 hours per week). The pupils' psychosocial well‐being was measured at the beginning and end of the school year using the Strengths and Difficulties Questionnaire. The results were compared between the groups.

Results: Pupils regularly exposed to EOtC showed the greatest improvement in prosocial behavior. Negative associations were seen between EOtC and hyperactivity‐inattention and peer problems in pupils of low socioeconomic status (SES). The observed improvements were smaller when the EOtC was spread over a larger number of sessions. Results were independent of sex.

Conclusions: Regular exposure to EOtC was found to promote social well‐being, especially for pupils of low SES, and was most beneficial when concentrated in fewer, longer sessions.