Disability includes permanent and temporary impairment of body function and structure. It is an ambiguous and multifaceted concept. It applies to almost all dimensions of life, and is relative with regard to the applicable norms and socio-cultural standards. Despite the scientific importance in medical, sociological, psychological, theological and pedagogical sciences, the concept is still not uniformly defined by the researchers.In the literature there are many definitions of disability, the most adequate is defined by the WHO, which defines disability as the health-related consequences (disease, disorder, resulting from genetic reasons or trauma), i.e. reduced possibility in functioning of man at three levels of existence: biological, personal and social.Using of multiple synonymous terms: disability, invalidity, infirmity, handicap, defect, etc. causes the freedom of interpretation, and makes it difficult to conduct research and to obtain by people with disabilities the due benefits and specific support.The paper presents a review of the definition and classification of disability.