Child support when your child turns 18

Normally child support stops when your child turns 18. If your child's in secondary study, you can apply to extend it to the end of the school year.

When to apply

You need to apply while your child’s 17. Your child must continue to attend secondary school full time after they turn 18. We’ll send you a letter to remind you to do this.

We’ll only accept an application after your child has turned 18 in some circumstances. The circumstances must:

  • be exceptional
  • be outside of your control
  • have prevented you from applying before your child turned 18.

Read the child support guide on the Department of Social Services website.

What happens to Family Tax Benefit if you don't extend child support

If you don’t extend it, you'll only get the base rate of Family Tax Benefit Part A for that child.

When you have a child support assessment

A child support assessment is when we assess the amount of child support you need to pay or receive.

You can apply to have your assessment extended for your eligible child before they turn 18. An eligible child is a child included in the case between you and the other parent or carer.

You can also apply to continue to include your relevant dependent child in your assessment. Read who can be a relevant dependent child.

When you have a child support agreement

A child support agreement allows parents to agree on the amount of child support to pay. You can register this agreement with us.

You can apply to extend your agreement for your eligible child before they turn 18.

First, you should review the terms of your current child support agreement. What you need to do next depends on whether:

  • you had a child support assessment in place before you made your child support agreement
  • your child support agreement started your child support case and you’ve never had a child support assessment.

If your child support assessment was in place before you made your agreement

Agreement ends before or when your child turns 18

If your child support agreement ends before or when your child turns 18, you can either:

  • extend the assessment to the end of the school year
  • negotiate a new agreement before your child turns 18 to continue your child support.

Only the parent who receives child support can apply to extend the assessment. A paying parent can’t ask for an extension.

Agreement ends after your child turns 18 or doesn’t have an end date

You can apply to extend the case if the existing agreement either:

  • ends after your child turns 18
  • doesn’t have an end date.

You can extend the case until the end of the school year or your agreement end date, whichever is earlier. If your agreement ends before the end of the school year, the assessment will continue until the school year ends.

In this situation, the parent who receives child support can apply to extend the case. A paying parent can’t ask for an extension.

If your agreement started your child support case

Agreement ends after your child turns 18 or doesn’t have an end date

You can apply to extend the existing agreement if it either:

  • ends after your child turns 18
  • doesn’t have an end date.

You can extend the case until the end of the school year or your agreement end date, whichever is earlier. To do this both parents must sign the Child over 18 years of age in full time secondary education form.

Agreement ends before or when your child turns 18

You can’t extend your agreement if it ends on the day your child turns 18.

But you and the other parent can make a new agreement before your child turns 18 to continue child support. You can then apply to extend the new agreement.

To do this both parents must sign the Child over 18 years of age in full time secondary education form.

You can’t extend your agreement if it ends before your child turns 18.

But either parent can apply for a child support assessment. Then the parent who receives child support can apply to extend the assessment before your child turns 18.

Both parents can also make a new agreement before your child turns 18 to continue child support. You can then apply to extend the new agreement. To do this both parents must sign the Child over 18 years of age in full time secondary education form.

What we consider full time secondary study

We consider your child to be in full time secondary study if either:

  • your child’s school says they’re in full time secondary study
  • your child turns 18 during a school holiday and will return to school at the end of the holiday.

The end of the school year is the later of either:

  • the last day of classes
  • the last day of your child’s exam period.

The school year can also include international school years.

How court orders can affect you

A court with family law jurisdiction may order maintenance for a child over 18 in some circumstances. You can register these orders with us for collection. Visit the Family Court of Australia for family law information.

How to apply

You can apply to extend your child support assessment, agreement or make a new agreement by:

Page last updated: 25 May 2020