Proposes a constitutional amendment that changes a valid marriage from a marriage between a man and a woman to two persons regardless of their genders

2026 Regular Session Introduced by Mark Boyko and 1 co-sponsor

Prop is a constitutional amendment to define marriage as between two persons, regardless of gender, in Missouri.

Referred: Emerging Issues(H)

#constitutionalamendments #familylaw #marriageanddivorce

Summary of Bill: HJR 166 (Missouri) – 2026

What the bill seeks to do

Proposes a constitutional amendment to Missouri’s state constitution.

Repeals the current provision that defines valid marriages as between a man and a woman.

Establishes that, moving forward, a marriage is valid and recognized in Missouri when it is between two persons, regardless of their genders.

The amendment would be submitted to Missouri voters at the next general election (Tuesday following the first Monday in November 2026) or at a special election if called by the governor.

Key provisions and changes

Repeals Section 33, Article I, of the Missouri Constitution and replaces it with a new Section 33.

New text (Section 33): “That to be valid and recognized in this state, a marriage shall exist between two persons regardless of their genders.”

The bill also clarifies formatting: bracketed text in the original section is not enacted; bolded text indicates proposed language. The substantive change is the shift from “a man and a woman” to “two persons.”

Who or what would be affected

Legal definition of marriage in Missouri Constitution.

State recognition and regulation of marriage would apply to marriages between two persons, regardless of gender.

Potential downstream effects on related state laws and policies that reference the constitutional definition of marriage (e.g., civil rights protections, family law, domestic relations, and certain governmental program eligibility). Specific administrative or statutory updates may be needed to align all state laws with the amended constitutional definition.

Procedural and timeline aspects

It is a joint resolution proposing a constitutional amendment, not an ordinary statute.

The amendment would be placed on the ballot for voter approval at:

The next general election in Missouri (the Tuesday next after the first Monday in November, 2026), or
A special election called by the governor for that purpose.

If approved by voters, the amendment becomes part of the Missouri Constitution and supersedes any conflicting language in Section 33, Article I.

Additional notes

The bill is similar in purpose to prior efforts (HJR 70 in 2025 and HJR 121 in 2024).

Primary sponsor: Representative Burton, with co-sponsors including Michael Burton and Mark Boyko.

Committee action history shows introduction in January 2026, and referral to Emerging Issues (H) in May 2026 for consideration.

Bottom line

HJR 166 seeks to constitutionalize the recognition of marriages between two persons, regardless of gender, effectively aligning Missouri’s constitutional definition with broader protections for same-sex and different-sex couples. The measure requires voter approval to take effect.