What Makes a Will Invalid in Illinois?

 Posted on June 20, 2025 in Estate Planning

When a will does not comply with Illinois law, it will likely be declared invalid. Working with an experienced Illinois estate planning attorney is the first line of defense in avoiding mistakes that can unravel your will and your wishes. Additionally, understanding the requirements for a valid will can help you protect your estate from costly litigation and ensure that your assets go exactly where you intend.

What Are the Legal Requirements for a Valid Will in Illinois?

The Probate Act of 1975 outlines the requirements for an Illinois will. According to 755 ILCS 5/4-3 of the act, a will must be in writing and signed by the testator, who is the person making the will. It can also be signed by someone acting on the testator’s behalf and by their direction. It must be signed in the presence of two or more credible witnesses. The testator must be at least 18 years old and of sound mind and memory. Failure to meet any of these conditions could result in the will being deemed invalid. 

What Are Undue Influence and Lack of Capacity?

A common reason for challenging a will in court is undue influence, which is when someone pressures or manipulates a testator into changing their will in a way that benefits the person influencing them. Courts will look for red flags, such as sudden, unexplained changes in beneficiaries or the involvement of a caretaker in drafting the will.

Another frequent issue is the lack of testamentary capacity, which means the testator did not understand the nature of their property or the meaning of their decisions at the time the will was made. If the testator was suffering from a mental illness or was under the influence of medication that clouded their judgment, the will could be contested under 755 ILCS 5/4-1 and other related probate provisions.

Common Mistakes That Invalidate an Illinois Will

Common errors made in good faith that can invalidate a will include:

• Using beneficiaries as witnesses, voiding their inheritance under 755 ILCS 5/4-6

• Failing to sign the will in the presence of witnesses

• Failing to have the witnesses sign separately

• Ambiguities in the language, such as unclear instructions about asset distribution

• Failing to properly revoke prior wills

• Making changes after execution without following proper amendment procedures

These oversights can lead to court challenges, delays in probate, or even full invalidation of the will. Consulting an attorney is the best way to avoid making mistakes.

Contact a Hyde Park, IL Estate Planning Attorney for a Free Consultation

If a will is declared invalid, the estate can be distributed according to a previous valid will or Illinois intestacy laws, which generally dictate that the estate passes to the closest living relatives. This can be devastating for your loved ones and lead to lengthy legal battles. The Flossmoor, IL estate planning lawyer at The Sherrod Law Firm, Ltd. is ready to assist with drafting or updating your will. Call us today at 312-321-6910 to schedule your free consultation.