The age of majority in Wisconsin is 18. On your eighteenth birthday, state law treats you as an adult for nearly every civil purpose: signing contracts, voting, owning property, controlling your own records, and answering for yourself in court. A few things still wait until 21, and one significant piece of Wisconsin law actually treats you as an adult a year earlier.
What the Statute Says
Wisconsin Statute 990.01(3) defines an adult as any person who has reached the age of 18.1Wisconsin State Legislature. Wisconsin Code 990.01 – Construction of Laws; Rules and Definitions That definition runs through the entire state code unless a specific statute sets a different age. The change happens at midnight on your eighteenth birthday. No paperwork, no filing, no court order. Your legal status changes on its own, whether you still live at home or are still finishing high school.
What You Can Do at 18
The most immediate practical change is the ability to enter binding contracts. Before 18, most contracts a minor signs are voidable, meaning you can walk away without legal consequence. After 18, a lease is enforceable, a car loan is your obligation, and a credit card balance can follow you into collections. You can open bank accounts, take out loans, and manage your finances without a co-signer.
You can also buy and sell real estate, take out a mortgage, and hold a deed in your own name. In court, you can sue and be sued directly, without a guardian ad litem standing in for you. That works both ways: judgments against you are yours to pay.
Voting rights begin at 18 for local, state, and federal elections. You can also apply for a U.S. passport on your own for the first time.2U.S. Department of State. Adult Passport
Privacy Shifts From Your Parents to You
Two federal privacy laws transfer control from parents to the new adult on the eighteenth birthday, and this one catches families off guard more than any other.
Under the Family Educational Rights and Privacy Act, your educational records become yours. Before 18, parents can see grades, disciplinary records, and other school files. Once you turn 18 or begin attending a postsecondary institution at any age, those rights transfer to you, and schools cannot release your records to your parents without your written consent.3U.S. Department of Education. FERPA – Protecting Student Privacy
Medical privacy works the same way under HIPAA. After 18, your medical records, treatment history, and health information are protected even from your parents. Being on a parent’s insurance plan doesn’t change this. A parent who calls a doctor’s office about a college-age child and gets told nothing is running into a HIPAA authorization the child hasn’t signed.
Obligations That Start at 18
Adulthood brings duties along with rights. Male U.S. citizens and immigrant non-citizens between 18 and 26 are required to register with the Selective Service System.4Office of the Law Revision Counsel. United States Code Title 50 Section 3802 Failing to register can block you from federal student financial aid, federal job training programs, federal employment, and, for immigrants, naturalization.
Turning 18 also makes you eligible for jury service. Federal law requires jurors to be U.S. citizens at least 18 years old who have lived in the judicial district for at least a year.5Office of the Law Revision Counsel. 28 U.S. Code 1865 – Qualifications for Jury Service Wisconsin state courts use the same age. A summons that arrives after your eighteenth birthday generally has to be answered.
What Still Requires 21
Turning 18 doesn’t unlock everything. Several significant privileges wait until 21, and confusing the thresholds can produce real criminal exposure.
- Alcohol. The legal drinking age in Wisconsin is 21. Wisconsin does have an unusual carve-out: a person under 21 can possess and consume alcohol on licensed premises if accompanied by a parent, guardian, or spouse of legal drinking age, though the establishment can refuse. An 18-year-old can legally have a drink with a parent at a bar and face criminal charges for the same drink alone or with friends.6Wisconsin Department of Revenue. Alcohol Beverage Laws for Retailers – Underage Alcohol Questions
- Tobacco. Federal law raised the minimum tobacco purchase age to 21 nationwide in December 2019. This covers cigarettes, e-cigarettes, cigars, and every other tobacco product sold in Wisconsin.
- Handguns. Under federal law, licensed firearms dealers cannot sell a handgun to anyone under 21. An 18-year-old can buy a rifle or shotgun from a licensed dealer, but handguns require the additional three-year wait.
Criminal Court Draws the Line at 17
Wisconsin is one of only a handful of states that automatically prosecutes 17-year-olds in adult criminal court rather than juvenile court. Civil adulthood begins at 18, but the criminal justice system treats you as an adult a full year earlier. A 17-year-old charged with a crime in Wisconsin faces the same court, the same sentencing guidelines, and the same permanent record as someone in their twenties. Serious felonies can pull younger teenagers into adult court through a waiver process, though the automatic threshold sits at 17.
Reaching Adult Status Before 18
Wisconsin recognizes a few narrow paths to adult legal standing before the eighteenth birthday, but none of them work by filing a petition.
Marriage
Someone between 16 and 18 can marry in Wisconsin with written parental or guardian consent. The consent must be given under oath before the county clerk or verified by a notary, and it is filed with the marriage license application.7Wisconsin State Legislature. Wisconsin Statutes 765.02 – Marriageable Age; Who May Contract If no parent or guardian is available and a state agency is the custodian, a court with probate jurisdiction can grant consent after a hearing. Under Wisconsin case law, marriage is treated as emancipation, and the married minor is regarded as an independent adult for most purposes.
Military Service
Enlisting in the armed forces with parental consent is the other recognized path. Like marriage, military service is treated as a decisive break from parental authority.
There Is No Emancipation Petition
Wisconsin has no emancipation statute. You cannot go to court and ask to be declared an adult. When a specific legal question arises, such as medical consent or financial liability, courts may look at whether a minor is functionally independent on the facts. In practice, marriage and military enlistment are the only two widely recognized triggers.
Parental Support That Runs Past 18
Turning 18 does not automatically end every parental financial obligation. Wisconsin Statute 767.511(4) requires courts to order child support for any child under 18, and the obligation extends to age 19 if the child is still pursuing a high school diploma or its equivalent.8Wisconsin State Legislature. Wisconsin Statutes 767.511 – Child Support A parent cannot stop paying in January because the child turned 18 if that child is finishing high school in June.
Past-due support accrues interest at 0.5% per month (6% annually), starting once the arrears equal or exceed one month’s payment.9Wisconsin Department of Children and Families. Child Support Enforcement Collection Methods A parent who falls behind can also face contempt of court, so the consequences of ignoring an order don’t soften as the child nears the cutoff.
Social Security Child Benefits
A child receiving Social Security benefits on a retired, deceased, or disabled parent’s record generally loses those benefits at 18. Benefits can continue until age 19, or until graduation if that comes first, when the child is still a full-time student at the secondary level (grade 12 or below).10Social Security Administration. Frequently Asked Questions – Students The student must attend at least 20 hours per week in a course lasting at least 13 weeks. College enrollment doesn’t qualify. Benefits can also continue over a summer break of four months or less if the student plans to return to secondary school afterward.
Custodial Accounts
If a parent or grandparent opened a custodial investment or savings account under Wisconsin’s Uniform Transfers to Minors Act, the custodianship typically ends at 21, not 18. At that point, the custodian hands over control and the assets become yours. Some custodianships terminate at 18 depending on how they were set up, so it’s worth checking the original account terms.