This article explores the legal status of sibling marriages in Japan, and the various factors that influence it. It examines the cultural and social attitudes towards such unions as well as examples of sibling marriages in Japanese history and culture. Additionally, it looks at the impact of international law on the legal status of sibling marriages in Japan. In general, there is still a strong stigma attached to sibling marriages in modern day Japan despite its historical prevalence during earlier periods in Japanese history. Understanding both historical context as well as current legal status can help individuals make informed decisions regarding whether they should pursue such relationships or not.