Yes, you can adopt someone over 18 in nearly every state. Adopting an adult is far simpler than adopting a child: both people sign a consent, one of you files a petition, a judge holds a short hearing, and the court issues a decree creating a legal parent-child relationship. There is no home study, no agency, and no need to involve the adoptee’s biological parents. The paperwork is easy. The consequences for inheritance, federal benefits, and immigration are where people get surprised.
Why People Do It
Inheritance is the most common reason. When someone dies without a will, state intestacy laws put spouses and children first. Adopting an adult gives that person the same legal standing as a biological child, ahead of siblings, nieces, nephews, and more distant relatives.
Stepparents, foster parents, and grandparents who raised a child but never formalized the relationship often use adult adoption to make the paperwork match the reality decades later. Caregivers of adults with disabilities use it to establish lasting legal authority over medical and financial decisions, which can be more durable than a guardianship or power of attorney.
Before same-sex marriage was legalized nationwide in 2015, some couples adopted each other to create a protected legal family relationship. A few have since tried to reverse those adoptions in order to marry, with mixed results in the courts.
Where State Law Gets in the Way
Roughly two-thirds of states allow any adult to adopt any other adult with little more than mutual consent. The remaining third impose real conditions.
The most common restriction is an age gap. Some states simply require the adopter to be older than the adoptee. Others set a specific minimum: 10 years in some jurisdictions, up to 15 in others. A few states go further and restrict adult adoption to people who already have a family-like relationship, such as stepparents, blood relatives, or former foster parents who stayed in contact after the child aged out of the system.
A small number of states are more restrictive still. At least one limits adult adoption to individuals who are permanently disabled or have an intellectual disability. Others require the adoptee to have lived in the adopter’s home for a minimum period, often two years, before the petition is filed.
Nearly every state that allows adult adoption prohibits adopting your own spouse. Many also prohibit adopting siblings, aunts, uncles, or other close blood relatives, because those relationships already carry legal weight. Some states cap how many unrelated adults a person can adopt in a given period to deter serial adoptions used for fraud. Check your state’s statute before you file.
Consent and Who Else Must Sign
Mutual consent is the core requirement everywhere. Both the adopter and the adoptee must voluntarily agree in writing, and the judge at the hearing will question both to confirm no one is being pressured.
If the adopter is married, spousal consent is required in most states, because a new legal heir affects the marital estate. Some jurisdictions extend that requirement to the adoptee’s spouse.
One thing that surprises people: the adoptee’s biological parents have no say. Unlike a minor adoption, there is no requirement to notify them or obtain their consent. The adoptee is a legal adult making their own decision.
Judges still screen for fraud. The petition describes the nature and length of the relationship, and the judge uses it to gauge whether the adoption serves a legitimate purpose. When the parties barely know each other, or when the adoptee has a disability that could make them vulnerable, courts are more likely to order a social services investigation before ruling. If the findings point to financial manipulation rather than a genuine family relationship, the petition will be denied.
How the Process Works
The petition is filed in the appropriate court, typically a family, probate, or surrogate’s court depending on the state. It includes signed consents from both parties, a description of the relationship, and the reasons for the adoption. A filing fee is due at submission. Fees vary widely, and hiring an attorney adds to the cost.
The court then schedules a hearing. In a straightforward case, it is brief: the judge reviews the paperwork, confirms both parties understand what they are doing, and asks about the relationship. Because there is no waiting period for biological parent consent, no home study, and no agency review, adult adoptions move much faster than child adoptions. Many are finished within a few months of filing. Cases involving investigations or objections take longer.
If the judge is satisfied the adoption is made in good faith, they issue a final decree. From that moment, the legal relationship is identical to a biological parent-child relationship.
What Legally Changes
The adopted adult gains the same inheritance rights as a biological child. If the adoptive parent dies without a will, the adopted adult inherits ahead of the adoptive parent’s siblings, parents, and extended family. If the adoptive parent is unmarried with no other children, the adopted adult may inherit the entire estate. The adoptee can also change their last name to the adoptive parent’s surname and request a new birth certificate.
The trade-off is real. Adoption generally severs the legal relationship between the adoptee and their biological parents. The adopted adult is no longer treated as a legal child of their birth parents for intestacy purposes. If a biological parent later dies without a will, the adopted adult has no automatic right to inherit. The severance runs both ways: biological parents also lose the right to inherit from the adopted adult. A will can override this and leave assets to the adopted-out child deliberately, but without one, the adopted adult may be excluded entirely.
The Trust Language Trap
Adult adoption can create unexpected problems with existing trusts. Many trusts distribute to a person’s “children,” “issue,” or “descendants,” and whether an adult adoptee qualifies under those terms depends on the trust language and state law. The answer is often no.
Most states and the Uniform Probate Code take the position that an adult adoptee does not count as a “child” for trust distributions made by someone other than the adoptive parent, unless the adoptee lived with the adoptive parent as a minor. A grandparent’s trust that distributes to “my grandchildren” may not include an adult-adopted grandchild, even though the adoption is valid for every other legal purpose. If including the adoptee in existing family trusts is part of the goal, review the trust language and applicable state law before filing, not after.
Where Adult Adoption Does Not Help
Federal programs apply their own definitions of “child,” and those definitions have age cutoffs. Adult adoption often does not unlock the federal benefits people expect.
Social Security pays survivor benefits to a deceased worker’s children only if the child is under 18, between 18 and 19 and in full-time elementary or secondary school, or any age with a disability that began before age 22.1Social Security Administration. Who Can Get Survivor Benefits A healthy adult adopted after 18 will not receive survivor benefits on the adoptive parent’s record.
The VA recognizes adopted children as dependents for disability compensation, pension, and dependency and indemnity compensation only if the child is under 18, between 18 and 23 and enrolled in school, or became permanently disabled before turning 18.2Veterans Affairs. Manage Dependents for Disability, Pension, or DIC Benefits A healthy adult adoptee does not qualify.
Immigration is the hardest cutoff. Federal law defines “child” for visa and citizenship purposes as someone adopted before age 16 who has been in the legal custody of and resided with the adoptive parent for at least two years.3Legal Information Institute. 8 USC 1101(b)(1) – Definition of Child A sibling of a qualifying adopted child may qualify if adopted before 18, but no one adopted as an adult meets the federal definition. Adult adoption cannot be used to sponsor an immigrant for a family-based visa or to confer automatic U.S. citizenship. Adults who were adopted as children but did not acquire citizenship before turning 18 can still apply for naturalization or lawful permanent residency through standard channels, but the adoption itself provides no immigration shortcut.4U.S. Citizenship and Immigration Services. Adult Adoptees and U.S. Citizenship
Can an Adult Adoption Be Reversed?
Sometimes. The person seeking reversal must file a petition and provide grounds. Courts have granted reversals when both parties consent, but some judges treat adoption as permanent absent fraud. If you are considering adult adoption with reversal as a fallback, assume it will be permanent and pursue it only if the relationship justifies a lasting legal bond.