The present study examined 310 students with mild intellectual disability (ID) who attended special schools and self-contained classes in mainstream schools with regard to their reports of depressive mood, and loneliness and social skills, and teachers' perception of the students' academic, social and behavioural competencies. A multivariate analysis of variance (MANOVA) revealed that: students in special schools reported higher levels of depression and felt lonelier than mainstream school students; girls exhibited a greater sense of depressive mood than boys; teachers assessed boys as having higher academic competencies than girls; and boys were considered more easily distracted and less independent. However, teachers considered girls to have more adequate social adjustment, and be more task-oriented and more independent. For both groups, depressive mood can be predicted by distractibility and loneliness; by gender and lower academic competencies for special school students; or mainly by difficulties in social adjustment in the case of mainstream school students.