Disability rights have expanded worldwide. About 125 countries have adopted anti-discrimination provisions, but we know less about the varying form of such provisions and how they affect rights-claiming. To analyze the variation, my presentation bridges theories of institutional change with the concept of “legal opportunity structures,” which illuminates features of the legal and judicial systems that shape how people mobilize the law. Through comparison of South Korea and Japan, this article shows how disability activists and lawyers transformed the structure of legal opportunities by demanding anti-discrimination legislation.