Background: Attention deficit hyperactivity disorder (ADHD) can severely harm academic achievement. Teachers are expected to be the first to observe behavioral abnormalities indicative of ADHD. The objective was to evaluate the efficacy of an educational program in improving the knowledge about ADHD among primary schoolteachers. Methods: An interventional pre-post study was conducted in one primary school (Zagazig, Egypt) from August 2023 to March 2024. After a pre-test, schoolteachers were given two-day educational intervention about ADHD in the form of lectures and discussion. A post-test was conducted three months after the intervention to assess teachers' retained knowledge regarding ADH. The Arabic version of the Knowledge of Attention Deficit Disorder Scale (KADDS) was used to assess teachers' knowledge about ADHD. Results Thirty-six schoolteachers included in the current analysis. Most of schoolteachers were 40 years or older (58.3%) and the majority (94.4%) were females. The majority of schoolteachers were college graduates (94.4%) and have work experience of 10 years or longer (83.3%). KADDS scores significantly increased from an average of 14.25±3.77 in pre-intervention phase to an average of 24.80±4.38 in the post-intervention phase (p<0.001), with 74.0% post-intervention improvement. The significant improvement was evident in the three ADHD knowledge aspects; general information, symptoms and diagnosis, and treatment, with post-intervention improvements of 73.6%, 57.5% and 95.0%, respectively. Conclusions: Educational interventions have proven beneficial in improving the knowledge of primary schoolteachers about ADHD. If teachers are equipped with sufficient knowledge about the disorder, they can play significant roles in detecting, referring, and managing the disorder