Does disability rights law impose an obligation on employers, schools, and other places of public accommodation to control the behavior of coworkers, students, or other third parties to accommodate an individual with disabilities? This Article examines that unexplored legal question and shows that the law frequently fails to protect people with disabilities from the choices and behaviors of third parties. Judges often consider these major barriers to access beyond the reach of the Americans with Disabilities Act’s reasonable accommodation mandate. This Article argues that this problem results from improperly imposing the privity paradigm, a doctrine that limits the inquiry about the reasonableness of an accommodation relative to the relationship between the first party (the disabled individual) and the second party (the employer or other entity covered by the Americans with Disabilities Act). Using disability studies, legal theory, and political economy analysis, this Article shows how a narrow interpretation of the reasonable accommodation mandate has failed to adapt to our modern understanding of disability as a complex interaction between the impairment and the social environment. To address the issue, this Article introduces a new theory of third-party accommodations, which would require others to alter or cease behaviors to accommodate an individual with disabilities. This Article then suggests a normative framework that courts can use to analyze cases involving requests for third-party accommodations, including the factors that judges should balance to determine the reasonableness of a request. In highlighting the need to move beyond a constricted interpretation of reasonable accommodation, this Article imagines a new horizon for disability justice.