Is there an age limit for adult adoption in Illinois?

Adult adoption in Illinois turns on your relationship with the adult, not on a stated age cutoff. The adult must be at least 18, and either of these must be true:

• Living together: the adult has lived in your home continuously for more than 2 years at any time before the case begins.
• Family relationship: you are related to the adult within the degrees listed in the "related child" definition of 750 ILCS 50/1. Those include parent, grandparent, sibling, step-parent, step-grandparent, step-sibling, uncle or aunt, and first or second cousin.

What about an upper age? Illinois's adult adoption rules give no maximum age for the adult being adopted, and they state no required age gap between you and the adult. If you have a specific age question, the Circuit Court clerk in your county can confirm it.

Your age as the adopter: you must be "a reputable person of legal age." A minor may adopt only by leave of court upon good cause shown.

Consent:

• Only the adult's consent is required. It must be in writing and acknowledged under 750 ILCS 50/10.
• The court may waive that consent if the adult needs mental treatment or has an intellectual disability.
• Consent from the adult's parents is optional. The statute provides a form for adults who choose to obtain it.
• If you are married or in a civil union, your spouse or partner generally must join the petition. A former stepparent adopting the adult is an exception.

Residency: you must have lived in Illinois continuously for at least 6 months before filing (members of the armed forces: domiciled 90 days). This rule does not apply when a former stepparent adopts the adult. Under 750 ILCS 50/4, the case can be filed in any county.