Objective: The purpose of the study is to differentiate between behaviors of ADHD: inattention, hyperactivity, and impulsivity and how each domain contributes to reading achievement in elementary school-aged children. Method: Data from 131 children were collected, which include performance from reading fluency and comprehension measures as well as parent and teacher ratings of ADHD behaviors based on the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) criteria. Results: Correlation and regression analyses revealed that inattentive behaviors were strongly linked to reading fluency and comprehension. Hyperactivity and impulsive behaviors did not predict reading achievement. A significant two-way interaction was found only for gender and inattention with reading comprehension as the outcome. Conclusion: Many of the behaviors related to inattention strongly predicted reading fluency, reading comprehension, and overall reading ability. Boys who exhibited inattentive behaviors performed more poorly on reading comprehension measures than girls with inattentive behaviors. (J. of Att. Dis. 2012; XX(X) 1-XX)