This chapter provides a comprehensive review of attention deficit hyperactivity disorder (ADHD) in children and adolescents, including diagnosis, neuropsychology, co-occurring conditions, and treatment interventions. A mixed methods approach was used, which included a literature review of relevant articles published between 1990 and 2023 and a case study vignette. The interventions discussed in the chapter cover a range of areas, including pharmacological, behavioral, and educational approaches, with the goal of improving the functioning and quality of life of individuals with ADHD. The case study vignette provides a practical illustration of how these interventions can be tailored to meet the unique needs of an individual with ADHD. Overall, this chapter presents a comprehensive understanding of the diagnosis and treatment of ADHD and comorbidities, and emphasizes the importance of personalized interventions for optimum results.