Background: In the debate on inclusive education, students without special educational needs (SEN) are an important topic. However, there is a lot unknown about differences between these typical students in inclusive and non-inclusive classes. For example, the neutral results that are often found in earlier research could be caused by positive effects for some students, and negative effects for others. Purpose: This study investigated whether there is a relation between inclusive education and the academic achievement and socio-emotional functioning of typical students, and, more importantly, whether inclusive education affects the achievement and socio-emotional functioning of more and less intelligent typical students differently. Furthermore, we investigated whether differences occur by type of SEN of the included students. Here, we made a distinction between students with behavioural, cognitive and other problems. Sample: A representative sample of 27,745 students without SEN in Dutch primary education from a large cohort study in the Netherlands was used. Design and methods: Language and arithmetic tests were used to assess academic achievement. For socio-emotional functioning, both teacher and student questionnaires were used. A non-verbal IQ test was used to assess student intelligence. Based on the number of students with diagnosed SEN, the students without SEN were divided into several groups: typical students with no, a few and more than a few students with (certain types of) SEN in their class. Multi-level regression analyses were used to compare these groups. Results: For academic achievement, no differences were found between students without SEN in inclusive and non-inclusive classes. In this, we found no differences between intelligent and less intelligent typical students. For socio-emotional functioning, some differences were found, but the practical importance of these differences is unclear, since the effect sizes were small. The functioning of typical students does not meaningfully differ by type of SEN of the included students. Conclusions: The findings of this study are interesting in the light of the ongoing inclusion debate. Arguments against inclusive education often concern an assumed adverse effect on typical students. As in this study, hardly any differences were found between typical students in inclusive and non-inclusive primary school classes, this research strengthens the scientific evidence in support of inclusive education. (Contains 12 tables and 4 notes.)