This essay explores the multifaceted aspects of intellectual disability, focusing on the support systems and specific needs of individuals affected by it. It begins with an operational definition, emphasizing limitations in intellectual functioning and adaptive behavior across conceptual, social, and practical domains. The essay highlights the importance of understanding the causes, which can be prenatal, perinatal, or postnatal, and the significance of gathering relevant information through history, evaluations, and living conditions to classify the severity of the disability. It then delves into the concept of support and needs, identifying them as common resources with varying intensities for disabled individuals, including normative, felt, comparative, and expressed needs. The essay references the human performance technology (HPT) model, outlining factors affecting human performance, and discusses the evolution of classification models, which now encompass IQ, adaptive behavior, health, participation, context, and support needs. It concludes by emphasizing the importance of clinical judgment, broad knowledge, and interaction with intellectually disabled individuals when classifying the severity of the condition and determining the necessary support systems.