Ohio: Prenuptial Agreement Requirements

Requirements one by one

Ohio uses a statute-plus-case-law framework

Ohio has not enacted the UPAA. R.C. 1335.05 supplies the signed-writing rule,
while the Ohio Supreme Court's Gross test, restated and refined in Fletcher v.
Fletcher, controls ordinary validity and enforceability. Current R.C. 3103.06
and 3103.061 separately govern a post-marriage modification or termination.

The Statute of Frauds requires a signed writing

R.C. 1335.05 bars an action on an agreement made upon consideration of marriage
unless the agreement, memorandum, or note is in writing and signed by the party
to be charged or that party's lawfully authorized agent. Unlike a UPAA
formation section, it does not say that the original agreement is enforceable
without consideration; it identifies marriage as the consideration category.

No notary or witness count appears in the governing rules

The writing statute requires a signature by the party to be charged. Neither it
nor the Gross/Fletcher validity test adds notarization, acknowledgment,
witnesses, attestation, an oath, or recording as a universal condition.

Disclosure or actual knowledge must be full

Gross requires full disclosure or full knowledge and understanding of the
nature, value, and extent of the prospective spouse's property. Ohio does not
use a UPAA written-disclosure-waiver formula.

Fletcher adds a burden rule for disproportionate agreements: when the challenger
would receive disproportionately less than under equitable distribution, the
party asserting validity must show full knowledge or disclosure. The challenger
still bears the burden on fraud, duress, coercion, or overreaching.

Counsel opportunity and wedding timing are linked

For a disproportionate agreement, Fletcher requires the financially
disadvantaged party to have a meaningful opportunity to consult independent
counsel. Actual representation is not an absolute condition; Fletcher says an
agreement signed without counsel is not invalid per se.

There is no fixed number of review days. But presentation a very short time
before the ceremony creates a presumption of overreaching or coercion when
postponement would cause significant hardship, embarrassment, or emotional
stress.

Gross supplies the three-part fairness test

A prenup must be entered freely without fraud, duress, coercion, or
overreaching; follow full disclosure or full knowledge and understanding; and
contain terms that do not promote or encourage divorce or profiteering by
divorce. Fletcher treats the spouses-to-be as occupying a fiduciary relationship
for this purpose.

Support terms receive a second look at divorce

Vanderbilt, applying Gross, explains that a support term may be challenged as
unconscionable at divorce. That review concerns enforcement of the support term,
not validity of the whole agreement. It asks whether circumstances materially
changed during marriage so that the term became unconscionable, guided by the
current R.C. 3105.18(C)(1) support factors.

Child issues remain with the court

R.C. § 3109.04(A) requires the court to allocate parental rights and responsibilities
according to the children's best interests. R.C. 3119.02 requires child support
to be calculated under the basic schedule, applicable worksheet, and the other
Chapter 3119 provisions. A prenup cannot replace those statutory court duties.

Post-marriage modification follows the 2023 statute

Since March 23, 2023, R.C. 3103.06(A)(2) permits spouses to modify or terminate
an antenuptial agreement. R.C. § 3103.061 requires a writing signed by both,
free execution, full disclosure or full knowledge and understanding of both
spouses' property, and terms that do not promote divorce. The change agreement
is enforceable with or without consideration.

What trips people up

• Ohio's original prenup rule is not R.C. 3103.05. That section concerns
  agreements between people who are already spouses. Original premarital
  enforceability comes from R.C. 1335.05 and Gross/Fletcher.
• No fixed waiting period means timing is fact-sensitive, not irrelevant.
  Fletcher's presumption depends on both last-minute presentation and the
  hardship, embarrassment, or emotional stress of postponement.
• The support second look does not reopen every property term. Vanderbilt
  describes an enforcement-time unconscionability review for the spousal-
  support provision.

Common questions

Must each person actually hire a lawyer?

Not in every case. Fletcher says lack of counsel is not automatically fatal, but
a financially disadvantaged party under a disproportionate agreement must have
a meaningful opportunity to consult independent counsel.

Can the spouses change the prenup after the wedding?

Yes. Current R.C. 3103.06 and 3103.061 provide a statutory post-marriage route,
but the change or termination must meet the signed-writing, voluntariness,
disclosure/knowledge, and no-divorce-promotion conditions.

Can a valid support waiver become unenforceable later?

Yes. A court may decline to enforce the support term if materially changed
circumstances make it unconscionable at divorce, using the R.C. 3105.18(C)(1)
factors to guide the review.

Statutes and sources

• Ohio Rev. Code § 1335.05 — signed-writing rule for an agreement made upon
  consideration of marriage. Official Ohio
  statute (accessed
  2026-07-27).
• Fletcher v. Fletcher, 68 Ohio St. 3d 464 (1994) — Gross test, burden shift,
  meaningful counsel opportunity, and short-timing presumption. Official Ohio
  opinion
  (accessed 2026-07-27).
• Vanderbilt v. Vanderbilt, 2014-Ohio-3652 — enforcement-time support
  unconscionability review and R.C. 3105.18(C)(1) factors. Official Ohio
  opinion
  (accessed 2026-07-27).
• Ohio Rev. Code §§ 3103.06 and 3103.061 — statutory post-marriage
  modification or termination route. Section
  3103.06 and section
  3103.061 (accessed
  2026-07-27).
• Ohio Rev. Code § 3105.18(C)(1) — spousal-support factors. Official Ohio
  statute (accessed
  2026-07-27).
• Ohio Rev. Code § 3109.04 — best-interest allocation of parental rights and
  responsibilities. Official Ohio
  statute (accessed
  2026-07-27).
• Ohio Rev. Code § 3119.02 — required child-support schedule and worksheet
  calculation. Official Ohio
  statute (accessed
  2026-07-27).