Background: Teachers spend longer time with children, so they are expected to be the first to observe behaviors indicative of attention deficit hyperactivity disorder (ADHD). Thus, teachers' knowledge about ADHD is vital. The objective of this study is to measure knowledge about ADHD among teachers in Zagazig district.

Methods: A cross-sectional study was conducted at a representative sample of primary schools in Zagazig district; 213 teachers were asked to complete knowledge of Attention Deficit Disorder Scale (KADDS).

Results: 75.2% of the studied teachers have inadequate ADHD knowledge. Studied teachers had particularly poor knowledge about general information and treatment of ADHD, while their knowledge about symptoms and diagnosis was fair. Educational level and previous attendance of courses about ADHD were significantly associated with better knowledge.

Conclusion: Primary school teachers in Zagazig district lack adequate knowledge about ADHD. Such poor knowledge could contribute to worsened outcomes in ADHD children. Therefore, the study recommends conducting educational programs about ADHD to improve teachers' knowledge about the disorder and incorporating educational materials about childhood mental health disorders into the curricula of the faculties of education.