The Americans With Disabilities Act (ADA) is one of America's most comprehensive pieces of civil rights legislation that prohibits discrimination and guarantees that people with disabilities have the same opportunities as everyone else to participate in the mainstream of American life—to enjoy employment opportunities, to purchase goods and services, and to participate in State and local government programs and services.

To be protected by the ADA, one must have a disability, which is defined by the ADA as a physical or mental impairment that substantially limits one or more major life activities, a person who has a history or record of such an impairment, or a person who is perceived by others as having such an impairment. The ADA does not specifically name all of the impairments that are covered. The ADA is located in the United States Code, beginning at 42 U.S.C. §12101.

The ADA prohibits discrimination on the basis of disability in the activities of places of public accommodations (businesses that are generally open to the public and that fall into one of 12 categories listed in the ADA, such as restaurants, movie theaters, schools, day care facilities, recreation facilities, museums, libraries, parks, and doctors' offices). The ADA requires newly-constructed or altered places of public accommodation—as well as commercial facilities (privately owned, nonresidential facilities such as factories, warehouses, or office buildings)—to comply with the ADA Standards. Private clubs and religious organizations are exempt from the ADA's title III requirements for public accommodations.

In Massachusetts, the Americans with Disabilities Act (ADA) serves as a federal law that protects individuals with disabilities from discrimination in various aspects of public life. The ADA's protections extend to employment, state and local government services, public accommodations, commercial facilities, transportation, and telecommunications. To be protected under the ADA, an individual must have a disability, which is defined as a physical or mental impairment that substantially limits one or more major life activities, have a history of such an impairment, or be perceived by others as having such an impairment. Public accommodations, which include a wide range of entities such as restaurants, schools, and doctors' offices, must be accessible to individuals with disabilities and comply with specific standards for new constructions and alterations. While the ADA provides comprehensive protections, private clubs and religious organizations are exempt from Title III, which covers public accommodations. Massachusetts also has state laws that complement the ADA, providing additional protections against disability discrimination.