Background: this study evaluated the effect of an educational intervention for increasing elementary school teachers’ ADHD knowledge, attitudes, and behavior.Method: Teachers from 12 schools who had at least one students with a definitive diagnosis of ADHD participated in the study and were allocated into either an intervention (n=31) or control group (n=27). Teachers’ ADHD knowledge, Attitude, and Behavior were assessed before and after intervention. Six-session participatory intervention were provided only for the intervention group.Results: Two mounts after the intervention, the intervention group scored significantly higher on all three outcomes (P≤0.001).Conclusion: The educational intervention significantly improved teachers’, knowledge, attitudes as well as their behaviors and strategies to manage children with ADHD. It is recommended that this program will incorporate into in-service training courses for primary school teachers as a means of facilitating teaching and managing children with ADHD in class. Trial registration: The study was approved by the by the Research Deputy of Isfahan University of Medical Sciences. In addition, The Ethical Committee of Isfahan University of Medical Sciences approved the study proposal. (ID code: IR.MUI.RESEARCH.REC.1398.297). The required permission from Education Department of Isfahan City was attained. Participation in the study was voluntary. Before taking part in the study, selected teachers provided written consent also study goals were described to them.