Child support in Illinois ends when the child turns 18 under 750 ILCS 5/505. If the child is still enrolled in high school at age 18, Illinois law extends child support until the child graduates or turns 19, whichever occurs first. Illinois courts may also order contributions to college expenses up to age 23 under 750 ILCS 5/513, and support for disabled adult children under 750 ILCS 5/513.5 has no age cap. The paying parent must file a motion to formally terminate the support order even after the child reaches the termination age.
Author: Antonio G. Jimenez, Esq. (Florida Bar No. 21022)
Key Facts: Child Support Termination in Illinois
| Item | Details |
|---|---|
| Standard Termination Age | 18 years old (750 ILCS 5/505) |
| High School Extension | Until graduation or age 19, whichever is first |
| College Expense Contributions | Up to age 23; age 25 with good cause (750 ILCS 5/513) |
| Disabled Adult Child | No age cap (750 ILCS 5/513.5) |
| Divorce Filing Fee | $250 to $388 depending on county (as of March 2026) |
| Residency Requirement | 90 days (750 ILCS 5/401) |
| Grounds for Divorce | No-fault only (irreconcilable differences) |
| Property Division | Equitable distribution |
| Child Support Model | Income Shares Model (adopted 2017) |
| Modification Review | Every 3 years or upon substantial change |
What Age Does Child Support End in Illinois?
Child support in Illinois terminates at age 18 under 750 ILCS 5/505, unless the child is still attending high school, in which case support continues until the child graduates or turns 19, whichever comes first. Age 19 is the absolute cutoff for standard child support obligations regardless of educational status.
Every Illinois child support order includes a specific termination date calculated based on the child's birth date and expected high school graduation. The support obligation does not end automatically when the child reaches the termination age. The paying parent must take action, either by filing a motion with the court or notifying the Illinois State Disbursement Unit, to formally stop income withholding payments. Until the order is formally modified or terminated, payments remain due and enforceable.
Unpaid child support arrearages survive past the termination date. Even after a child turns 18 or 19, any past-due amounts the paying parent owes remain fully collectible. Illinois courts can enforce arrearages through wage garnishment, tax refund intercepts, license suspension, and contempt of court proceedings. The statute of limitations on collecting child support arrearages in Illinois is 20 years from the date the payment was due.
Does the High School Rule Change When Child Support Ends in Illinois?
Illinois extends child support past age 18 only if the child is still enrolled in and attending high school at the time of their 18th birthday. The extension continues until high school graduation or the child's 19th birthday, whichever occurs first, per 750 ILCS 5/505. A child who graduates before turning 18 does not trigger early termination; support continues to age 18.
The high school extension applies only to traditional secondary education, not GED programs or alternative education tracks. Courts evaluate whether the child is actively pursuing a high school diploma through regular attendance. If the child drops out of high school after turning 18, the paying parent can file a motion to terminate support immediately rather than waiting for the 19th birthday. The following table summarizes the four common scenarios Illinois families encounter:
| Scenario | When Support Ends |
|---|---|
| Child graduates high school before age 18 | Age 18 |
| Child turns 18 and has already graduated | Age 18 |
| Child turns 18 while still in high school | Graduation or age 19 (whichever is first) |
| Child turns 19 without graduating | Age 19 (hard cutoff) |
How Does Emancipation Affect Child Support in Illinois?
Emancipation can end Illinois child support obligations before the child reaches age 18 or 19, but emancipation is not automatic under 750 ILCS 5/510. A parent seeking to terminate child support based on emancipation must file a formal Petition to Terminate Child Support with the Illinois court, serve the other parent, and prove the child is self-supporting or otherwise legally emancipated.
Common events that parents mistakenly believe trigger automatic emancipation include the child moving out of the custodial parent's home, obtaining full-time employment, joining the military, or getting married. None of these events automatically terminate child support in Illinois. Each requires a court determination. The petitioning parent bears the burden of proving the child has achieved financial independence or that circumstances warrant an emancipation finding.
The court evaluates several factors when ruling on emancipation petitions, including the child's income relative to their living expenses, whether the child maintains a separate residence, whether the child is financially dependent on either parent, and the child's maturity and decision-making capacity. If the court grants emancipation, the judge enters a formal order terminating the child support obligation as of a specific date. The other parent has the right to contest the petition and present evidence that the child is not truly self-supporting.
Can Illinois Courts Order College Expense Contributions After Child Support Ends?
Illinois is one of a minority of states that allows courts to order divorced parents to contribute to their children's college and post-secondary educational expenses under 750 ILCS 5/513. College expense contributions are separate from and in addition to regular child support. The obligation can extend until the child's 23rd birthday, or the 25th birthday if good cause exists such as illness or military service.
Section 513 covers tuition and fees, on-campus or off-campus housing, medical insurance, dental expenses, books and supplies, up to 5 college application fees, up to 2 standardized test fees (SAT or ACT), and 1 test preparation course. Illinois caps the contribution amount at the cost of attending the University of Illinois at Urbana-Champaign as an in-state student. For the 2025-2026 academic year, that cap translates to approximately $17,000 to $18,000 in tuition and fees plus $12,000 to $13,000 in room and board, totaling roughly $30,000 per year.
The child must maintain at least a C average (2.0 GPA) to remain eligible for parental contributions under Section 513. Courts consider the present and future financial resources of both parents, the standard of living the child would have enjoyed had the marriage continued, and the child's own financial resources when determining each parent's share. A parent who wants to seek college contributions must file a petition, and the obligation applies retroactively only to the date the petition was filed. Parents cannot recover college expenses incurred before filing the petition.
What Happens to Child Support for a Disabled Adult Child in Illinois?
Illinois courts can order child support to continue indefinitely for adult children with disabilities under 750 ILCS 5/513.5. Unlike standard child support (capped at age 18 or 19) and college contributions (capped at age 23 or 25), support for disabled adult children has no statutory age limit. Either parent can file a petition for disabled adult child support before or after the child turns 18.
The statute defines disability as a physical or mental condition that significantly limits major life activities, including the ability to work, communicate, or live independently. Courts assess the functional impact of the condition rather than relying solely on a medical diagnosis. Evidence typically includes medical evaluations, treatment histories, vocational assessments, and documentation of any government disability benefits the child receives.
Support payments for disabled adult children can be directed to one parent, split between both parents, or paid irrevocably into a special needs trust established for the child's benefit. Trust arrangements are common because direct payments to the disabled adult child could disqualify them from Supplemental Security Income (SSI) and Medicaid benefits. A properly structured special needs trust preserves government benefit eligibility while supplementing the child's care. Either parent may petition for modification based on a substantial change in circumstances, including significant income changes or improvements in the child's condition.
How Is Illinois Child Support Calculated Under the Income Shares Model?
Illinois uses the Income Shares Model to calculate child support, adopted in 2017 to replace the previous percentage-of-income formula. Under 750 ILCS 5/505, both parents' net incomes are combined to determine the total child support obligation using a statutory schedule, and each parent's share is proportional to their percentage of combined income.
The Income Shares Model accounts for the number of children, each parent's gross income minus allowable deductions (taxes, Social Security, health insurance premiums, existing support obligations), and the number of overnight parenting time each parent exercises. When a parent has the child for 146 or more overnights per year (40% or more of overnights), the shared parenting formula applies, which reduces the basic support obligation to reflect the additional costs the non-custodial parent incurs during their parenting time.
Illinois courts can deviate from the calculated amount if applying the guideline amount would be unjust or inappropriate. Deviation factors include extraordinary medical expenses, educational needs, the standard of living the child would have enjoyed had the family remained intact, and the financial resources of each parent. Any deviation must include a written finding explaining why the guideline amount is inappropriate. Courts review child support orders every 3 years upon request, or sooner if either parent demonstrates a substantial change in circumstances such as job loss, significant income increase, or a change in parenting time.
What Is the Process for Terminating Child Support in Illinois?
Terminating child support in Illinois requires the paying parent to file a Petition to Terminate Child Support with the court that issued the original order, even when the child has reached the age specified in the order. Under 750 ILCS 5/510, the court must formally modify or vacate the support order before income withholding stops. Simply stopping payments without a court order exposes the paying parent to contempt proceedings and arrearages.
The termination process follows these steps:
- Verify the child has reached the termination age specified in the court order (18, or up to 19 if still in high school)
- Confirm no arrearages exist by requesting an account statement from the Illinois State Disbursement Unit
- File a Petition to Terminate Child Support in the original court
- Serve the petition on the other parent
- Attend the court hearing where the judge confirms the child's eligibility for termination
- Obtain the signed order terminating support
- Provide the termination order to the employer currently withholding child support
If the child support order was established through the Illinois Department of Healthcare and Family Services (HFS) rather than through a divorce proceeding, the administrative review process differs. HFS conducts periodic reviews of child support orders and can administratively close a case when the child ages out. However, parents should not rely solely on the administrative process and should independently verify that their obligation has been formally terminated.
How Do Illinois Residency Requirements Affect Child Support Cases?
At least one spouse must have resided in Illinois for a minimum of 90 days immediately before filing a divorce petition under 750 ILCS 5/401. Military personnel stationed in Illinois for 90 or more days satisfy this requirement. Illinois courts can establish child support jurisdiction over a non-resident parent if the child resides in Illinois under the Uniform Interstate Family Support Act (UIFSA).
Illinois is a no-fault divorce state, meaning the only ground for dissolution is irreconcilable differences. If the spouses have lived separate and apart for 6 months or more, the court applies an irrebuttable presumption that irreconcilable differences exist. The 90-day residency requirement and the 6-month separation period can run concurrently, meaning a spouse who has been an Illinois resident and separated for at least 6 months can file and proceed without delay.
Divorce filing fees in Illinois range from $250 to $388 depending on the county. Cook County (Chicago) charges the highest filing fee at $388, with an additional $250 appearance fee for the responding spouse. Most counties outside Cook County charge between $250 and $350 for the initial petition. Fee waivers are available for households at or below 125% of the federal poverty guidelines. As of March 2026, verify current fees with your local circuit clerk before filing.
What Recent Changes Affect When Child Support Ends in Illinois?
Illinois made several procedural adjustments to child support law in 2024 and 2025, though the core termination rules under 750 ILCS 5/505 remain unchanged. The 2024 legislative session eliminated the accrual of interest on child support arrearages, a significant change for parents with outstanding balances. The 2025 session introduced stricter enforcement penalties for non-payment and enhanced income verification standards for self-employed parents and parents with variable income such as bonuses and commissions.
The Income Shares Model formula itself, adopted in 2017, has not been substantively modified. The shared parenting calculation received minor adjustments in 2024 to address how overnight counts affect the support amount in cases where parents exercise nearly equal parenting time. Illinois continues to align with federal Title IV-D requirements under the Social Security Act, which govern state child support enforcement programs.
Parents with existing child support orders can request a modification review every 3 years through the Illinois Department of Healthcare and Family Services or file a motion with the court at any time based on a substantial change in circumstances. Qualifying changes include a 20% or greater change in either parent's income, a significant change in parenting time, changes in the child's medical or educational needs, or changes in either parent's legal obligation to support other dependents.
Frequently Asked Questions
Does child support automatically stop at 18 in Illinois?
Child support does not automatically stop at 18 in Illinois. Although 750 ILCS 5/505 sets 18 as the standard termination age, the paying parent must file a Petition to Terminate Child Support with the court. Income withholding continues until a judge signs a termination order. Unpaid arrearages remain enforceable for 20 years.
When does child support end in Illinois if my child is still in high school?
Illinois extends child support past age 18 if the child is actively attending high school at the time of their 18th birthday. Under 750 ILCS 5/505, support continues until the child graduates or turns 19, whichever occurs first. Age 19 is the absolute cutoff regardless of whether the child has graduated.
Can I be ordered to pay for my child's college in Illinois?
Yes. Under 750 ILCS 5/513, Illinois courts can order divorced parents to contribute to college expenses until the child turns 23, or 25 with good cause. Contributions are capped at the University of Illinois at Urbana-Champaign in-state rate, approximately $30,000 per year for tuition, fees, and housing in 2025-2026. The child must maintain a 2.0 GPA.
How do I stop paying child support in Illinois?
To formally stop child support in Illinois, file a Petition to Terminate Child Support in the court that issued the original order under 750 ILCS 5/510. Serve the other parent, attend a hearing, and obtain a signed termination order. Provide the order to your employer to stop wage withholding. Never stop payments without a court order.
Does getting married emancipate my child and end child support in Illinois?
A child's marriage does not automatically emancipate them or terminate child support in Illinois. Under 750 ILCS 5/510, the paying parent must file a Petition to Terminate Child Support based on emancipation and prove the child is self-supporting. The court makes the final determination. Marriage can serve as evidence of emancipation but is not sufficient on its own.
What if my child has a disability — does child support continue indefinitely?
Yes. Under 750 ILCS 5/513.5, Illinois courts can order child support to continue indefinitely for adult children with physical or mental disabilities that significantly limit major life activities. There is no age cap. Payments can be directed to a special needs trust to preserve the child's SSI and Medicaid eligibility.
How much does it cost to file for divorce in Illinois?
Illinois divorce filing fees range from $250 to $388 depending on the county, as of March 2026. Cook County charges the highest fee at $388 for the petition plus $250 for the respondent's appearance. Fee waivers are available for households at or below 125% of the federal poverty guidelines. Verify current fees with your local circuit clerk.
Can child support be modified before the termination date in Illinois?
Yes. Either parent can petition for child support modification at any time based on a substantial change in circumstances under 750 ILCS 5/510. Qualifying changes include a 20% or greater income change, significant parenting time changes, or new medical or educational needs. Parents can also request a routine review every 3 years through the Illinois Department of Healthcare and Family Services.
What is the 90-day residency requirement for divorce in Illinois?
At least one spouse must have been an Illinois resident for a minimum of 90 consecutive days immediately before filing under 750 ILCS 5/401. Military personnel stationed in Illinois for 90 days also qualify. A spouse can file the petition before completing 90 days, but the court cannot enter a final judgment until the requirement is met.
Does Illinois use the income shares model for child support?
Yes. Illinois adopted the Income Shares Model in 2017, replacing the previous percentage-of-income formula. Under 750 ILCS 5/505, both parents' net incomes are combined to calculate the total support obligation from a statutory schedule. Each parent pays their proportional share. The shared parenting formula applies when the non-custodial parent has 146 or more overnights per year (40% of overnights).