Everything engaged couples need to know about making a prenuptial agreement valid and enforceable in Wisconsin — in plain English, reviewed by attorney James Sexton, Esq.
Yes — prenuptial agreements are legal and enforceable in Wisconsin as marital property agreements under Wis. Stat. § 766.58.
Wisconsin runs on a genuinely different system from most states. It is the only state to adopt the Uniform Marital Property Act, codified as the Wisconsin Marital Property Act (Wis. Stat. ch. 766, effective 1986). That makes Wisconsin effectively a community property state: income and assets acquired during marriage are presumed marital property owned equally by both spouses, regardless of whose name is on them. A prenup in Wisconsin is technically a marital property agreement under Wis. Stat. § 766.58 — it must be in writing and signed by both spouses, requires no consideration, and can reclassify property, control what happens at divorce or death, and keep individual property individual.
A Wisconsin marital property agreement is enforceable when it is written, signed by both spouses, made voluntarily after fair disclosure, and fair under the Button v. Button test — both when signed and when enforced.
Wis. Stat. § 766.58(1) requires a signed writing; no consideration is necessary. Oral agreements have no effect.
Under § 766.58(6), the agreement is unenforceable against a spouse who proves involuntary execution, unconscionability when made, or that they received no fair and reasonable disclosure and had no notice of the other's finances.
Button v. Button, 131 Wis. 2d 84 (1986) requires procedural fairness — adequate disclosure, time to review, opportunity for counsel — and substantive fairness in the terms at execution.
Wisconsin adds a second look: under Wis. Stat. § 767.61(3)(L), a property agreement binds the divorce court unless its terms are inequitable to either party at that time. Significantly changed circumstances can unwind an agreement that was fair when signed.
| Governing statute | Wisconsin Marital Property Act — marital property agreements, Wis. Stat. § 766.58; Button v. Button, 131 Wis. 2d 84 (1986) |
|---|---|
| Property division | Community property (marital property) |
| Notarization | Recommended (not required by statute) |
| Waiting period | None required — but sign well before the wedding |
| Spousal support | Maintenance terms allowed, but reviewed for fairness at divorce |
See how Wisconsin's signing formalities compare in our prenup notarization requirements by state guide. Wisconsin is also one of the nine community-property states — community property vs. equitable distribution explains what that default means for your agreement.
Wisconsin courts set marital property agreements aside when disclosure was inadequate, signing was rushed, or the terms are inequitable — judged both at signing and again at divorce under Button v. Button.
Wisconsin gives prenups a distinctive double fairness check. Button v. Button requires the agreement to be procedurally and substantively fair when signed, and Wis. Stat. § 767.61(3)(L) lets a divorce court decline to follow terms that have become inequitable by the time of divorce — for example, after an unforeseen illness or a decades-long marriage the agreement never contemplated. The practical answer is to disclose fully, sign early, keep terms reasonable, and revisit the agreement when life changes materially.
Trusted Prenup creates a state-specific Wisconsin prenuptial agreement online — built to meet the requirements above and designed by James Sexton, Esq. A traditional attorney typically costs $2,500–$10,000; this is a flat $599.
A guided questionnaire captures your assets, debts, and wishes — most couples finish in under 90 minutes.
We assemble a complete prenup built to meet your state's exact legal requirements.
Review with your partner, then sign online with notarization handled for you.
A Wisconsin attorney-drafted marital property agreement typically costs $2,000–$6,500. Trusted Prenup creates a state-specific Wisconsin prenup online for a flat $599, with optional notarization and attorney-review add-ons.
No — Wis. Stat. § 766.58 requires only a document signed by both spouses. Notarization is still recommended, since a notarized signature is much harder to dispute in a later challenge.
Yes — and Wisconsin gives challengers two windows. Under § 766.58(6) and Button v. Button, an agreement fails if it was involuntary, unconscionable, or made without fair disclosure; and under § 767.61(3)(L) a divorce court can set aside terms that have become inequitable by the time of divorce.
Effectively, yes. Wisconsin is the only state that adopted the Uniform Marital Property Act, so property acquired during marriage is presumed marital property owned 50/50 by both spouses. A marital property agreement is how couples opt out of those defaults.
It's Wisconsin's statutory name for a prenup (or postnup) under Wis. Stat. § 766.58. The agreement can classify property as individual or marital, direct what happens at divorce or death, and cover property whenever and wherever acquired.
You can include maintenance terms, but Wisconsin courts review them for fairness at the time of divorce under the Button framework — a waiver that leaves one spouse in hardship after changed circumstances may not be enforced.
Yes — Wisconsin enforces properly executed prenuptial agreements regardless of how they were drafted. What matters is execution: a written agreement, voluntary signatures, full financial disclosure, and Wisconsin's signing formalities. The full picture is in are online prenups legally binding.
Trusted Prenup is not a law firm and does not provide legal advice. This guide is general information about Wisconsin law and not a substitute for advice from a licensed attorney about your situation.