Japan’s six nationwide same-sex marriage lawsuits have produced conflicting high court rulings, with five finding the current legal framework unconstitutional and one finding it constitutional. The final second-instance ruling came from the Tokyo High Court on Nov. 28, 2025, making it the only high court among the six cases to uphold the existing provisions.
The Tokyo High Court held that the term “marriage” in Article 24 of the Constitution refers to the historically established union between people of different sexes. It therefore concluded that same-sex de facto relationships do not fall within the constitutional guarantee of marriage. On Article 14 and equality before the law, the court said lawmakers had not been completely inactive and that parliamentary debate should continue.
The ruling differed from decisions by the Sapporo, first Tokyo, Fukuoka, Nagoya and Osaka high courts, all of which found constitutional problems with the provisions excluding same-sex couples from marriage. In March 2026, the Supreme Court transferred all six appeals to its Grand Bench, composed of all 15 justices, bringing the cases together for a unified constitutional review.
After the Tokyo ruling, the plaintiffs and their legal teams announced that they would appeal. They subsequently asked the Supreme Court to hear the cases in the Grand Bench and to hold oral arguments so that the parties could present their views directly.
The central constitutional issues include Articles 14(1) and 24, as well as the scope of legal protection available to same-sex couples. The five high court rulings that found the provisions unconstitutional relied principally on equality, individual dignity and constitutional principles governing marriage and family. The Sapporo and Fukuoka decisions also addressed marriage freedom and the right to pursue happiness.
The Grand Bench consists of all 15 Supreme Court justices. As of March 2026, all six same-sex marriage appeals had entered the Grand Bench process, although no final ruling date had been announced. The Supreme Court’s interpretation will determine how the disputed provisions are assessed under Japan’s Constitution.
Asian Editorial Department: Kim Min-jun