This document provides an overview of disability concepts and issues. It discusses the definition of disability according to the WHO and various classification systems. Approximately 15% of the global population lives with some form of disability. In India, the 2011 census found over 26 million persons with disabilities, around 2.21% of the population. Disabilities can be physical, sensory, intellectual, or mental and are caused by disease, trauma, or other health conditions. Evaluation of disability is important for service provision and policymaking. Barriers to healthcare and increased vulnerability affect those with disabilities. The document outlines concepts, statistics, and policy frameworks related to understanding disability worldwide and in India.