The goal of the present study was to determine whether a web-based medium is an effective tool for supporting knowledge, attitude, and behavior change in teachers of elementary school children with attention-deficit/hyperactivity disorder (ADHD). Nineteen teachers from Nova Scotia, Canada completed a 7-week intervention that consisted of presentations, web links, and discussion board activities related to different aspects of ADHD. Teachers' knowledge positively changed from pre- to post-intervention (p = .03), as did teachers' attitudes related to perceived control in their classrooms (p = .001) and competence in teaching (p < .0001). The study demonstrated that a web-based medium is a useful tool for knowledge creation and translation and has potential as a means of providing professional development to teachers about ADHD.