This paper aims at identifying and reflecting on disabled people from the perspective of the Systems theory and the most relevant related elements. The purpose is to contribute to acquiring knowledge on disability, mainly as an element that will help practitioners understand this phenomenon, not as an isolated issue but as a bio-psycho-social integration. To achieve this goal, initially, a description of disability as a system itself will be carried out. Secondly, disability with reference to other systems will be described and thirdly, disability under the bio-psycho-social model will be analyzed from the holistic perspective of the WHO health proposal.