Background: Attention Deficit Hyperactivity Disorder is the most common childhood neuropsychiatric disorders that become apparent in both preschooler and schooler children. Attentive deficit hyperactive Children often have other comorbid psychiatric disorders, such as conduct and sleep disorders, anxiety, and depression. The aim of the study: to investigate attention deficit hyperactivity disorder and its relationship to sleep and conduct disorders among school-age children.Design: A descriptive correlational research design was utilized in this study. Setting: This study was carried out at Children's Psychiatric Outpatient Clinic at Port Said Psychiatric Health Hospital. Sample: A convenience sample of 125 parents accompanying their children who suffering from attention deficit hyperactivity disorder and attending to the previously mentioned setting for 6 months. Tools of data collection: self-administered structured interview questionnaire and child sleep habits questionnaire were used. Results: 80.0% of the study children with attention deficit hyperactivity disorder had disturbed sleep and 12.8% of them have conduct disorders. Conclusion:the studyconcluded that attention deficit hyperactivity disorder has a strong statistically significant positive correlation with total sleep and conduct disorders. Recommendation: Parents' training programs should be developed to increase parenting skills in managing their child's behavior, facilitating social skills development, encouraging parents' positive interaction with their child.