Introduction: Paving the way towards inclusive education, it is essential to aim for positive social outcomes for all students, including cultivating a positive self-concept and fostering acceptance and friendships with peers. Although self-concept, acceptance and friendships are interrelated, research focussing on the relationship between these constructs remains limited. Method: This study examined the self-concept, acceptance and friendships of two groups of typically developing students in secondary education (n = 401) and two groups of students in special secondary education with either an intellectual disability (ID) (n = 58) or social, emotional and behavioural difficulties (SEBD) (n = 68). Results: Lower self-concept scores were found for students with ID on some dimensions, whereas typically developing students reported lower acceptance and friendship scores. Multilevel analyses indicated that acceptance is a predictor for several different dimensions of self-concept in the different groups of students, but friendship is less likely to predict self-concept scores. Discussion: The results of the study emphasize the importance of promoting peer acceptance amongst all students in inclusive school settings in order to realize the intended positive social outcomes of inclusive education.