Japan does not recognize gay marriage at the national level. It is the only Group of Seven country without a legal framework that allows same-sex couples to marry, and marriages performed in other countries carry no legal status when the couple returns home. What exists instead is a patchwork: roughly 530 municipalities issue partnership certificates with limited practical effect, a 2023 federal law acknowledges that discrimination is “unacceptable” without creating enforceable protections, and a series of court rulings since 2021 has found the marriage ban unconstitutional in various ways. The Supreme Court is now set to issue the country’s first definitive ruling on the question.
Why There Is No National Marriage Law for Same-Sex Couples
The obstacle is Article 24 of the Japanese Constitution: “Marriage shall be based only on the mutual consent of both sexes and it shall be maintained through mutual cooperation with the equal rights of husband and wife as a basis.”1Japanese Law Translation. The Constitution of Japan The national government reads “both sexes” as requiring one man and one woman, and local administrative offices will not process marriage registrations for same-sex couples on that basis.
Plaintiffs challenging the ban argue the clause was written in 1947 to stop families from forcing women into marriages, not to define who may marry whom. On that reading, the operative word is “consent,” not “sexes.” The Supreme Court has never squarely resolved the question, and that gap is what has driven more than a decade of litigation.
What Municipal Partnership Certificates Actually Provide
Beginning with Tokyo’s Shibuya Ward and Setagaya Ward in 2015, local governments started creating partnership certificate programs to fill the gap left by national law. As of mid-2025, around 530 municipalities had adopted these systems, covering an estimated 92.5 percent of the population, and more than 9,800 couples had received certificates.
These are administrative documents, not marriage licenses. Tokyo’s program explicitly notes that, unlike marriage, the partnership oath is not legally binding.2Tokyo Metropolitan Government. Tokyo Partnership Oath System User Guide What they do accomplish is practical. A certificate can help a couple:
- Access public housing reserved for family units
- Visit each other in hospitals that would otherwise restrict access to relatives
- Be named as life insurance beneficiaries in some cases
- Qualify for spousal benefits at companies that accept the certificates as documentation, including employers such as Nintendo Japan and Panasonic
What a certificate cannot do matters more. It carries no weight under the Civil Code. That means no inheritance rights, no joint tax filing, no recognized legal relationship when a couple crosses into a municipality without its own program. Recognition depends entirely on the local address.
The Financial Cost of Not Being Married
The practical gap shows up most sharply in inheritance and tax law. Under the Civil Code, a surviving legal spouse automatically inherits at least half the estate when there are children, two-thirds when the deceased’s parents are the closest relatives, and three-quarters when siblings are the closest relatives. A same-sex partner has no automatic inheritance rights, because the Civil Code reserves spousal status for legally recognized spouses.3Japanese Law Translation. Civil Code – Article 890
A will can direct assets to a partner, but the tax treatment is harsh. Japan’s inheritance tax gives married spouses a credit that shelters either their statutory share or 160 million yen (roughly $1 million), whichever is larger.4Ministry of Finance of Japan. Structure of Inheritance Tax A same-sex partner inheriting the same assets qualifies for none of that relief and also faces a 20 percent surcharge on the calculated tax because they are not a legal heir. Lifetime gifts between partners are subject to gift tax above 1.1 million yen per year; married couples can transfer certain assets tax-free.
Marriages Performed Abroad
A Japanese citizen who marries a same-sex partner in a country where such marriages are legal returns to a relationship with no legal status in Japan. The foreign spouse of a Japanese citizen cannot obtain the standard “Spouse or Child of a Japanese National” visa that different-sex couples use.
A narrow workaround exists where both partners are foreign nationals. If one holds valid residence status in Japan, the other can apply for a “Designated Activities” visa based on the marriage. The Ministry of Justice created this pathway as an administrative accommodation; it does not amount to recognition of the marriage, and it does not extend to Japanese-foreign couples, who often rely on unrelated categories such as work or student visas to live in the same country. Foreign marriages also carry no legal weight for joint property ownership, medical decision-making, or parental rights under Japanese jurisdiction.
Children and Parental Rights
Joint adoption requires a legal marriage under the Civil Code, which effectively bars same-sex couples from adopting together. No statute explicitly prohibits a single LGBT individual from adopting, but the system is built around married couples and the practical barriers are high. A same-sex couple in Osaka was approved as foster parents in 2016, but that case stands as an exception rather than an established route.
When a same-sex couple raises a biological child, only the biological or legally adoptive parent holds parental authority. The non-biological partner has no recognized legal relationship with the child: no custody rights, no authority over medical decisions, no automatic guardianship if the legal parent dies. Partnership certificates do not change this, because parental authority is governed by the national Civil Code.
The 2023 LGBT Understanding Act
In June 2023, Japan passed the Act on the Promotion of Public Understanding of the Diversity of Sexual Orientation and Gender Identity, known as the LGBT Understanding Act. It establishes a basic principle that discrimination based on sexual orientation or gender identity is “unacceptable” and directs the national government to formulate a basic plan for promoting public understanding.5Japanese Law Translation. Act on the Promotion of Public Understanding of the Diversity of Sexual Orientation and Gender Identity
The law’s reach is deliberately soft. Employers and schools are told to “endeavor” to promote understanding and improve environments for sexual minorities, but there are no penalties for inaction and no enforceable anti-discrimination protections. The law says nothing about marriage equality. It acknowledges that discrimination exists without providing tools to address it.
The Court Rulings and What Comes Next
Since 2021, coordinated lawsuits in courts across Japan have produced a strikingly consistent pattern. Four of the five district court rulings on the marriage ban found constitutional problems with it; the Osaka District Court was the only outlier, ruling in June 2022 that the ban was constitutional. Grounds for the rulings against the ban varied, pointing to Article 14’s guarantee of equality before the law, Article 24(2)’s requirement that family laws respect individual dignity, or both.
The appellate wave has been even stronger. The Sapporo High Court became the first appeals court to rule, in March 2024, finding the ban violated Article 24(1), Article 24(2), and Article 14(1) — the strongest decision issued to that point.6The Asahi Shimbun. High Court – Lack of Provisions for Gay Marriage Unconstitutional The Tokyo High Court followed in October 2024, and in March 2025 both the Nagoya and Osaka High Courts found the ban violated Article 24(2) and Article 14(1). A separate Tokyo High Court panel broke the pattern in November 2025, ruling that the ban does not violate the Constitution and that the legislature retains broad discretion to define marriage.
None of these rulings changes the law directly. Japanese courts can declare a statute unconstitutional, but only the National Diet can amend the Civil Code. What the rulings create is political and legal pressure that has grown with each decision.
In March 2026, the Supreme Court assigned the question to its Grand Bench, the panel of all fifteen justices reserved for major constitutional questions. Ordinary Supreme Court cases are heard by five-justice panels that can only apply existing precedent; the Grand Bench can establish new precedent, which is what the marriage question requires. A ruling finding the ban unconstitutional would not legalize same-sex marriage on its own, but it would put heavy pressure on the Diet to legislate. A ruling upholding the ban would settle the constitutional question for the foreseeable future. The decision is expected as early as 2027, and it will be the first time Japan’s highest court has directly addressed whether the Constitution’s “both sexes” language prohibits same-sex marriage or merely fails to address it.