Illinois Will Requirements: How to Write a Legally Valid Will

Illinois probate courts reject wills that fail to meet the state's execution requirements — and the mistakes are almost always avoidable. A will written at the kitchen table with good intentions but wrong formalities is legally identical to having no will at all, which means the estate defaults to Illinois intestacy rules and a judge decides who gets what.

Here are the exact requirements under the Illinois Probate Act (755 ILCS 5/).

Who Can Make a Will in Illinois

The testator (person making the will) must be:

• At least 18 years old
• Of sound mind and memory at the time of signing

"Sound mind" means the testator understands the nature of the document, knows the general extent of their property, and can identify their natural heirs (spouse, children, close relatives). A diagnosis of dementia does not automatically disqualify someone — the standard is capacity at the moment of signing.

Signing and Witness Requirements

Illinois requires the will to be:

1. In writing — typed or printed. Illinois does not recognize holographic (entirely handwritten, unwitnessed) wills.
2. Signed by the testator — or by someone else at the testator's direction and in their presence.
3. Witnessed by at least two people — each witness must be at least 18 and must sign in the testator's presence.

The witnesses do not need to read the will or know its contents. They need to see the testator sign (or acknowledge a previously made signature) and then sign the document themselves.

Who Can Witness a Will in Illinois

Illinois does not require "disinterested" witnesses — meaning a beneficiary named in the will can legally serve as a witness. However, using interested witnesses invites challenges. The safer practice is choosing two adults who are not named in the will, not related to the testator, and not the testator's attorney or financial advisor.

The notary public who notarizes the will (if you add a self-proving affidavit) cannot count as one of the two required witnesses.

The Self-Proving Affidavit

A self-proving affidavit is an optional but strongly recommended addition. It is a notarized statement attached to the will in which the testator and witnesses swear under oath that the will was properly executed. Under 755 ILCS 5/6-4, a self-proved will can be admitted to probate without requiring the witnesses to appear in court to testify.

Without the affidavit, the probate court must locate at least one original witness to verify the signatures — which can cause significant delays if witnesses have moved, become incapacitated, or died.

The affidavit must be signed by the testator and both witnesses in front of a notary public. The notary cannot also serve as a witness.

What the Will Should Cover

At minimum, an Illinois will should address:

• Property distribution — who receives specific assets and who receives the residuary estate (everything not specifically named)
• Executor nomination — who manages the estate through probate
• Guardian nomination — who raises minor children if both parents die
• Bond waiver — whether the executor must post a surety bond (waiving it saves $460 to $600 annually)
• Independent administration — whether the executor can act without court approval for routine transactions (recommended to reduce costs and delays)

What a Will Cannot Do in Illinois

A will does not control assets with existing beneficiary designations — life insurance, retirement accounts, POD bank accounts, and TOD investment accounts all pass outside the will. Joint tenancy property passes to the surviving owner automatically. And a Transfer on Death Instrument (TODI) on real estate overrides whatever the will says about that property.

This is why a will is necessary but not sufficient for a complete Illinois estate plan.

Getting It Right

The Illinois Basic Estate Planning Kit includes a will execution checklist with the exact witness and notary requirements, a self-proving affidavit template, and a guide to coordinating the will with beneficiary designations and non-probate transfers so nothing falls through the cracks.

See more Illinois guides →