Missouri: Will Execution Requirements

Requirements one by one

Governing law

Missouri now has two execution tracks. Sections 474.310 through 474.360 govern
traditional written wills. The Electronic Wills and Electronic Estate Planning
Documents Act, §§ 474.540 through 474.564, took effect August 28, 2025 and
applies to wills of decedents dying on or after that date. Section 474.544 makes
an electronic will a will for all purposes unless the newer act modifies the
ordinary rule (§ 474.544). The decedent-death applicability date comes from
§ 474.564.

Minimum age and capacity

Section 474.310 permits a will by a person of sound mind who is at least 18 or
by a minor emancipated through adjudication, marriage, or entry into active
military duty. The 2025 electronic-wills act changes the medium and ceremony,
not that capacity rule.

Writing and signature

A traditional will must be in writing and signed by the testator or by someone
acting at the testator's direction and in the testator's presence. An electronic
will must be a record readable as text when signed and remain accessible as text
for later reference. It is signed by the testator or by another individual in
the testator's name, physical presence, and direction.

Witnesses required

Both routes require at least two witnesses. Traditional witnesses subscribe
their names in the testator's presence under § 474.320. Electronic witnesses
sign after witnessing the signing or the testator's acknowledgment and may act
in the testator's physical or electronic presence. “Electronic presence” means
real-time, live interactive audio-video communication allowing observation,
interaction, and communication.

Section 474.330's competency and interested-witness rules still apply. A gift
to an interested witness can be reduced to the intestate-share amount unless
two disinterested witnesses also attest.

Notarization and self-proving

Notarization is not part of either basic validity ceremony. It is used for
optional self-proof. A traditional will uses § 474.337. An electronic will may
use the same method or, when fewer than two witnesses are physically in the
same location as the testator for the acknowledgments, a remote online notary
and the certificate described in § 474.550.

Handwritten wills

Missouri still has no unwitnessed holographic-will exception. A handwritten
document can be a traditional will if it satisfies § 474.320, but handwriting
alone does not replace the two witnesses. The electronic-will act is a separate
two-witness route, not a holographic exception.

Electronic and remote wills

Missouri permits both. Section 474.548 requires a readable electronic record,
the testator's compliant signature, and signatures from at least two witnesses
in physical or electronic presence. Extrinsic evidence may establish that the
testator intended the record to be the electronic will.

The law also recognizes an electronically executed will made under qualifying
law of the signing jurisdiction, the testator's domicile, or the testator's
residence under § 474.546. Remote witnessing still requires the live interactive
audio-video relationship defined in § 474.542; asynchronous email or recorded
video is not that definition.

Harmless error and foreign execution

Missouri has no general statute admitting a defective will merely because the
testator's intent is clear. The cross-border rules are different: § 474.360
recognizes a traditional written will executed under listed Missouri, signing-
place, domicile, abode, or nationality law, and § 474.546 supplies the electronic
counterpart for signing-place, domicile, or residence law.

What trips people up

The electronic-wills act did not remove the two-witness requirement. It changed
the record and presence rules: the will may be electronic and witnesses may use
live interactive audio-video presence, but the testator and two witnesses still
must complete the statutory ceremony.

Self-proof is optional but the witness-location overlay matters. Section
474.548(3) adds state-residency and physical-location language when no
self-proving affidavit is signed contemporaneously. Remote execution should be
planned with the self-proving route, not improvised after signatures are applied.

Common questions

Can my witnesses join by live video?

Yes, for a compliant electronic will. The communication must be real-time and
interactive so the participants can observe and communicate with one another,
and the witnesses sign after seeing the signing or acknowledgment.

Does an electronic will need a remote notary?

Not for basic validity. A remote online notary is one way to make the electronic
will self-proved when fewer than two witnesses are physically with the testator
for the acknowledgments.

Can I handwrite a will with no witnesses?

No. Handwriting does not create an exception to Missouri's two-witness rule. A
handwritten will may qualify only if it satisfies the ordinary execution statute
or another applicable law recognized by § 474.360.

Statutes and sources

• Mo. Rev. Stat. §§ 474.310, 474.320, and 474.330 — capacity, traditional
  signature and witness ceremony, witness competency, and interested-witness
  effect. § 474.310,
  § 474.320, and
  § 474.330
  (accessed 2026-08-01).
• Mo. Rev. Stat. §§ 474.337 and 474.360 — traditional self-proof and
  cross-border execution. §
  474.337 and §
  474.360
  (accessed 2026-08-01).
• Mo. Rev. Stat. §§ 474.542, 474.544, and 474.546 — electronic presence,
  signing definitions, full will status, and foreign electronic execution. §
  474.542, §
  474.544, and §
  474.546
  (accessed 2026-08-01).
• Mo. Rev. Stat. §§ 474.548, 474.550, and 474.564 — electronic signature
  and witness ceremony, remote self-proof, and applicability. §
  474.548, §
  474.550, and §
  474.564
  (accessed 2026-08-01).