The datasets correspond to the three studies conducted for my thesis. Study 1 contains data from direct testing and observation of the children with Attention-Deficit/Hyperactivity Disorder (ADHD) as well as questionnaires collected from their parents and teachers. Study 2 examined the parental factors that affect these children. The dataset of Study 2 contains questionnaire information collected from the parents of children with ADHD. Study 3 is a parenting intervention research on the parents of children with ADHD. The data set of Study 3 contains questionnaire information provided by the parents and teachers of the children.