BackgroundThere are indications that teachers have limited knowledge about attention deficit hyperactivity disorder (ADHD), despite its high prevalence in childhood and its long-term effects on students such as academic underachievement, reduced self-esteem, and social and behavioural difficulties. This study is therefore aimed at assessing the effect of an ADHD training program on the knowledge of ADHD among primary school teachers in Kaduna, Nigeria and their attitudes towards pupils with ADHD.MethodsThis was a randomized controlled trial involving 84 primary school teachers in the intervention group and 75 teachers in the control group. Participants in the intervention group received an initial 3-h training with a one-and-a-half hour booster session 2 weeks later using the World Health Organisation MhGAP-IG module on behavioural disorders focusing on ADHD. Outcome measures were knowledge of ADHD, attitude towards ADHD, and knowledge of behavioural intervention.ResultsControlling for baseline scores, the intervention group had significantly higher post intervention scores on knowledge of ADHD, lower scores on attitude towards ADHD (i.e. less negative attitudes), and higher scores on knowledge of behavioural intervention compared with the control group respectively. The intervention showed moderate to large effect sizes. The booster training was associated with a further statistically significant increase in knowledge of ADHD only.ConclusionsThe training program significantly improved the knowledge and attitudes of the teachers in the intervention group towards ADHD. Considerations should be given to incorporating ADHD training programs into teacher-training curricula in Nigeria, with regular reinforcement through in-service training.