Self-reports from children below primary age are rarely used in assessments of psychopathology. This study uses a version of the Strengths and Difficulties Questionnaire (SDQ), previously validated for children 11-15 years, to assess the internal validity of self-reports of psychopathology from primary aged children. The SDQ was completed by primary aged children (N = 1118). The sample consisted of children who had been referred to a school counselling service. The internal validity and the factor analytical structure of the child self-reports was examined. Self-reports given by infant school-aged children (4-7 years) did not fit well with predicted factor structures, indicating that they may not have been able to report consistently or accurately on their own emotions and behaviour. However, results indicated that junior school-aged (7-11 years) children may be able to report accurately on their own symptomology. These children’s reports appeared to distinguish well between internalising and externalising symptoms and fitted the hypothesized structure. However, there was some question of whether children are able to distinguish hyperactivity from other types of psychopathology. This study indicated that junior school-aged children may be able to report reliably on some aspects of their emotional and behaviour difficulties.