Teachers are often some of the first adults who suspect that a child is exhibiting symptoms of Attention-deficit hyperactivity disorder (ADHD). Much research suggests that teachers must be knowledgeable about ADHD to best make referral decisions that can positively affect the outcomes for children with the disorder, but to date, little research has been conducted regarding teachers' knowledge of ADHD in school-aged females. The current study examined the ADHD knowledge of sixty-four public school general education teachers and investigated potential differences in teachers' decisions to refer female and male students exhibiting the same inattentive ADHD symptoms for further evaluation. Findings suggest that teachers were most knowledgeable about the nature, causes, and impact of the disorder and less knowledge about the symptoms, diagnosis, and treatment of ADHD. Teachers also appeared to recognize that females with the disorder are likely underdiagnosed and can potentially face negative outcomes because of this. Teachers were less knowledgeable about the three ADHD presentations (primarily inattentive, primarily hyperactive/impulsive, and combined), and they may not be aware that females tend to exhibit symptoms which align more closely with the primarily inattentive presentation of the disorder. General education teachers were also more knowledgeable than special area teachers regarding the nature, symptoms, diagnosis, and treatment of ADHD, and teachers' confidence in working with students with the disorder also positively impacted their knowledge. No significant relationships were found between teachers' referral decisions based on student sex, suggesting that perceived impairment may be more important to teachers when deciding to refer students for further evaluation. Findings from this study suggest a need for further research in the area of teachers' knowledge of ADHD in females. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]