ABSTRACT Research into the self-concept of students with an intellectual disability (ID) or social, emotional and behavioural difficulties (SEBD) educated in special education is relatively scarce. This, whilst many students with ID or students with SEBD still reside in special rather than inclusive school settings. This study aimed to gain insight into the self-concept of students with either ID or SEBD in special education and examined variables that might relate to the self-concept of these students. A total of 171 students educated in special schools filled out the Self-Perception Profile for Children (SPPC). T-tests utilising bootstrapping and variance analyses were used to analyse the data. The results indicate that girls with ID and boys with SEBD assess their self-concept more negatively than typically developing students. Gender, age and formally assessed classifications of ASD or ADHD yielded different self-concept scores in both groups of students on different dimensions of self-concept. The expected positive illusory bias was not found in this study. The results of the study are discussed in light of the educational setting of the students with ID or students with SEBD. This study demonstrates that interventions are needed to improve the self-concept of students with ID or students with SEBD in special education.