This article examines the legal status and social attitudes towards polygamy in Japan, as well as how common it is. Polygamy was once widely practiced in Japan, but has been illegal since 1872. It is considered a criminal offense punishable by up to three years' imprisonment or a fine of up to 500,000 yen (about US$4,600). Japanese society generally has a negative view towards polygamy and those who engage in it are seen as immoral or even criminal. Despite its illegality and social stigma associated with it, polygamy does still exist on a much smaller scale than before due largely to its prohibitive costs and legal consequences. The impact of polygamy on modern-day Japanese society includes both positive aspects such as increased autonomy for women and financial security, but also concerns over an increase in domestic violence against women due to lack of legal rights.