In this dissertation, I argue that attempts by activists and policy makers to improve access to Japan’s built environment, education, employment, entertainment, and welfare systems for disabled populations over the last one hundred and fifty years have not always helped impaired individuals and frequently excluded as many demographics as they empowered. To identify which groups of people have been privileged with access and why, I analyze government records, news reports, and documents from advocacy organizations using approaches from history, anthropology, sociology, political science, and media studies. My evidence suggests that economic pressures tied to processes such as industrialization, democratization, and ageing have played a key role in shaping the politics of accessibility in modern Japan, as they have led architects, engineers, educators, and other stakeholders to focus on the needs of individuals with diverse impairments at different points in time. Equally influential have been international flows of information, materials, and people in the disability welfare sphere, which have pushed politicians to pursue domestic reforms. My project demonstrates why scholars of Japan must explore technologies created by and for disabled people to fully appreciate numerous aspects of the country’s culture, ranging from military actions and modes of governance to marketplace and material innovations. It also explains why academics interested in social justice issues in places like the United States and Europe must strive to investigate the history and politics of disability in Japan. Why does Japan matter? Because Japan has the third largest economy and fastest ageing population in the world. Interested parties often export its assistive technologies overseas, and the nation’s access-making activities have served, and likely will continue to serve, as successful models to emulate and cautionary tales of what to avoid for other countries. A descriptive project with prescriptive implications, this dissertation uses history to shape policy by asking policy makers to consider who has a seat at the table, how they come to be there, and what they fail to imagine when making access measures. By unpacking the politics of access in Japan’s past and present, this project helps create an inclusive future.