The use of education outside the classroom (EOtC) in schools is increasing; however, there are currently few studies assessing the longer-term impacts on academic achievement. The aim of the present study was to investigate the association between one school-year of regular (more than 2.0 h a week) participation in EOtC and Danish primary school children's reading performance. We conducted a quasi-experimental study involving 20 EOtC intervention group classes and 10 comparison group parallel classes (Grades 3–6). Children were tested pre- and post-intervention in reading performance. We found that exposure to EOtC had a small positive impact on test scores. The implication that regular EOtC is positively associated with reading performance is discussed.