ADHD is one of the most common chronic conditions of childhood. Teachers are a valuable source of information with regard to referral and diagnosis of the disorder. They also play a major role in creating an environment that is conducive to academic, social and emotional success for children with ADHD. The aim of this study was to examine primary school teachers' knowledge of the symptoms and management of children in their classrooms who were diagnosed with ADHD. The participants were 200 South African primary school teachers (178 female, 22 male; mean age = 43 years) of children enrolled in Grades One to Four. A self-administered questionnaire, the Knowledge of Attention-Deficit Disorder Scale (KADDS), which measures the misperceptions and understanding of the disorder, was used to collect the data. The results indicated that overall, 45% of the teachers correctly identified the responses to the items asked in the questionnaire. The "don't know responses" accounted for 31% of responses, while 22% of the responses were incorrectly identified. Furthermore, teachers were more knowledgeable of the general associated features of ADHD than of symptoms, diagnosis and treatment. A majority of teachers indicated that they had received training. These findings suggest a need to consider improving evidenced-based classroom interventions for ADHD among South African teachers.