Wyo. Stat. § 20-2-101 (2026)

(a) Marriages contracted in Wyoming are void without any
decree of divorce:

          (i) When either party has a husband or wife living at
the time of contracting the marriage;

          (ii) When either party is mentally incompetent at the
time of contracting the marriage;

          (iii) When the parties stand in the relation to each
other of parent and child, grandparent and grandchild, brother
and sister of half or whole blood, uncle and niece, aunt and
nephew, or first cousins, whether either party is illegitimate.
This paragraph does not apply to persons not related by
consanguinity;

          (iv) When either party is under sixteen (16) years of
age at the time of contracting the marriage.

     (b) A marriage is voidable if solemnized when either party
was sixteen (16) or seventeen (17) years of age unless a judge
gave consent, if they separated during nonage and did not
cohabit together afterwards, or if the consent of one (1) of the
parties was obtained by force or fraud and there was no
subsequent voluntary cohabitation of the parties.

     (c) Either party may file a petition in the district court
of the county where the parties or one (1) of them reside, to
annul a marriage for reasons stated in subsections (a) and (b)
of this section and proceedings shall be held as in the case of
a petition for divorce except as otherwise provided. Upon due
proof the marriage shall be declared void by a decree of
nullity.

     (d) An action to annul a marriage on the ground that one
of the parties was under the age of legal consent provided by
W.S. 20-1-102(a) may be filed by the parent or guardian entitled
to the custody of the minor. The marriage may not be annulled on
the application of a party who was of the age of legal consent
at the time of the marriage nor when it appears that the
parties, after they had attained the age of consent, had freely
cohabited as man and wife.

     (e) An action to annul a marriage on the grounds of mental
incompetency may be commenced on behalf of a mentally
incompetent person by his guardian or next friend. A mentally
incompetent person restored to competency may maintain an action
of annulment, but no decree may be granted if the parties freely
cohabited as husband and wife after restoration of competency.

     (f) An action to annul a marriage on the grounds of
physical incapacity may only be maintained by the injured party
against the party whose incapacity is alleged and may only be
commenced within two (2) years from the solemnization of the
marriage.

     (g) All decrees of annulment may include provisions for
the custody and support of children pursuant to this article,
W.S. 20-2-201 through 20-2-204 and 20-2-301 through 20-2-315 and
for the division of property pursuant to W.S. 20-2-114.