In every school across the world the need for class assistant that tolerates differences and specialness of all children is more and more recognizable. There is no arranged model of education for achieving competences that are necessary for doing this job in the Republic of Croatia. In this thesis legal frames of including children with developmental difficulties in regular school system are submitted, it is explained who the class assistants are, what their role is and what their mission is. One of those common difficulties with which the class assistant encounters is ADHD. ADHD is a developmental disorder of disturbed self-control of a pupil. Main characteristics of pupils that have ADHD are inattention, impulsiveness and hyperactivity. It is very important to notice these symptoms as soon as possible so that the ADHD could be diagnosed and treated accordingly. ADHD therapies could be carried out by interventions that are directed at a child and its family members and, in the end, with medications. The pupil that has been diagnosed with ADHD has bigger problems during education, therefore it is important that it receives valid approach and appropriate support. Class assistant is obliged to cooperate with parents, teachers and associates in order to get a quality education for the child with ADHD. Consistency is one of the preconditions for pupil’s success, therefore it is necessary to introduce code of conduct and the awarding system of a pupil to which all will adhere. Being a good class assistant means to be flexible while working with the pupil, to be responsible and completely devoted in doing this job with the aim of improving the quality of pupil’s education.