Intellectual Disability — What IDEA and Section 504 Mean for Schools and Families Intellectual Disability (ID) is an IDEA eligibility category and a condition that may also qualify a student for protections under Section 504 .  ID affects intellectual functioning and adaptive behavior across conceptual, social, and practical domains and can significantly impact learning, independence, and participation in school.  This article explains how a child qualifies, the referral and evaluation process, common assessments, evidence‑based supports, classroom accommodations and modifications , and parents’ rights. Legal Definitions and Frameworks IDEA: Intellectual Disability (previously “mental retardation”) is defined under IDEA as significantly subaverage intellectual functioning, existing concurrently with deficits in adaptive behavior, and manifested during the developmental period, that adversely affects educational performance and requires specially designed instruction . ...