FSA eligible dependents fall into three groups: your legal spouse, your children through the end of the year they turn 26, and other relatives or household members who meet the IRS “qualifying relative” test. Your health Flexible Spending Account can reimburse qualified medical expenses for anyone in those categories, and the rules are meaningfully more generous than the rules for claiming someone as a dependent on your tax return. Get the category wrong, though, and the IRS treats the reimbursement as taxable income, so the distinctions are worth understanding before you submit a claim.
Your Spouse
A legally married spouse is eligible automatically. The federal government recognizes any marriage that was legally performed in any U.S. state or jurisdiction, regardless of where you currently live.1Internal Revenue Service. Notice 2014-1 – Guidance on the Application of United States v. Windsor and Revenue Ruling 2013-17 You can submit claims for your spouse’s medical costs as soon as the marriage is finalized. There is no income limit, no residency requirement, and no need to claim your spouse as a tax dependent.
Domestic partners and civil union partners do not get this automatic eligibility. The IRS is explicit that “spouse” and “marriage” do not include registered domestic partnerships, civil unions, or similar arrangements that aren’t denominated as marriage under state law.1Internal Revenue Service. Notice 2014-1 – Guidance on the Application of United States v. Windsor and Revenue Ruling 2013-17 A domestic partner can still qualify, but only through the qualifying relative path described below.
Children Through Age 26
Your children are eligible through the end of the calendar year in which they turn 26. Under 26 U.S.C. §105(b), a child does not need to live with you, depend on you financially, or appear on your tax return as a dependent for their medical costs to be covered.2Office of the Law Revision Counsel. 26 USC 105 – Amounts Received Under Accident and Health Plans The statute requires only that the child has “not attained age 27” as of the end of the tax year.
This broad rule came in with the Affordable Care Act. Before the ACA, plans could drop adult children based on residency, student status, or financial independence. Those factors no longer matter.3U.S. Department of Labor. Young Adults and the Affordable Care Act: Protecting Young Adults and Eliminating Burdens on Businesses and Families FAQs Your 24-year-old who lives in another state and earns their own salary is as eligible as your teenager at home.
The IRS defines “child” to include biological children, stepchildren, adopted children, and eligible foster children.4Internal Revenue Service. Publication 502 – Medical and Dental Expenses Married children also qualify. Co-pays, prescriptions, and other qualified medical expenses can go through your FSA without any proof of financial support. Eligibility ends on December 31 of the year the child turns 26.
Disabled Adult Children Over 26
If your child is permanently and totally disabled, there is no age cutoff. A child who qualifies as your dependent under the standard qualifying-child rules in §152(c) is not subject to the usual age limits when the disability exception applies.4Internal Revenue Service. Publication 502 – Medical and Dental Expenses A 35-year-old with a permanent disability can remain FSA-eligible indefinitely, provided they meet the other qualifying-child requirements: they must not have provided more than half of their own support for the year, and they must not have filed a joint tax return except to claim a refund.
Even if a disabled adult child earns some income, the §105(b) rules disregard the gross income test that normally applies to qualifying relatives.2Office of the Law Revision Counsel. 26 USC 105 – Amounts Received Under Accident and Health Plans Families frequently miss this. If you provide the majority of a disabled adult child’s financial support, their medical expenses can flow through your FSA regardless of their age.
Parents and Other Qualifying Relatives
Family members who don’t fit the spouse or child categories can still be eligible if they meet the “qualifying relative” test under 26 U.S.C. §152(d). This is the path for an aging parent, an adult sibling, or a domestic partner. The requirements are stricter than for children, and documentation matters more.
The Support Test
You must provide more than half of the person’s total financial support for the calendar year.5Office of the Law Revision Counsel. 26 USC 152 – Dependent Defined Total support includes food, lodging, clothing, education, medical and dental care, recreation, and transportation.6Internal Revenue Service. Publication 501 – Dependents, Standard Deduction, and Filing Information For lodging, the IRS uses fair rental value rather than your actual mortgage or rent payment. Fair rental value means what you could reasonably charge a stranger for the same living arrangement, including a reasonable allowance for furniture and utilities.
Keep records showing that your contributions exceed both what the person spends on themselves and what everyone else combined contributes. Elderly parents are where this trips people up. Social Security and pension income counts as support the parent provides for themselves, and that can push your share below the 50% threshold if you’re not tracking carefully.
The Relationship or Residency Test
The person must either be a specific type of relative or live with you for the entire year as a member of your household.5Office of the Law Revision Counsel. 26 USC 152 – Dependent Defined Relatives who qualify without needing to live with you include your parents, grandparents, siblings, stepparents, nieces and nephews, aunts and uncles, and in-laws (sons-in-law, daughters-in-law, fathers-in-law, mothers-in-law, and siblings-in-law). Adopted children are treated the same as biological children.
Someone not on that list, such as a domestic partner or a close friend, can still qualify if they live with you for the entire calendar year as a member of your household. The person cannot have been your spouse at any point during the year and claim this path.
The Gross Income Test Is Waived
A detail that catches even tax professionals off guard: a qualifying relative normally must have gross income below a specific threshold ($5,050 for 2024, adjusted annually) to be claimed as a tax dependent. For health FSA reimbursement, §105(b) tells you to ignore that limit.2Office of the Law Revision Counsel. 26 USC 105 – Amounts Received Under Accident and Health Plans The statute defines dependents under §152 “determined without regard to subsection (d)(1)(B),” which is the gross income requirement.
In practice, an elderly mother who collects $25,000 a year in Social Security and pension income can still be FSA-eligible, as long as you provide more than half of her total support and she meets the relationship test. You could not claim her as a dependent on your tax return because of the income limit. You can still cover her medical expenses through your FSA. This gap between tax-dependent rules and FSA-dependent rules is one of the most underused benefits in the code.
Children of Divorced or Separated Parents
When parents are divorced, legally separated, or have lived apart for the last six months of the calendar year, a special rule applies. Under §105(b), any child covered by the divorced-parent provisions of §152(e) is treated as the dependent of both parents for health plan reimbursement.2Office of the Law Revision Counsel. 26 USC 105 – Amounts Received Under Accident and Health Plans Both parents can use their respective FSAs for the child’s medical expenses, even though only one parent claims the child on their tax return.
For §152(e) to apply, two conditions must be met. The child must receive more than half of their total support from the parents combined during the calendar year, and the child must be in the custody of one or both parents for more than half of the year.5Office of the Law Revision Counsel. 26 USC 152 – Dependent Defined When both conditions are satisfied, each parent has independent FSA access for that child’s medical costs. Neither parent needs permission from the other to submit claims, and neither parent’s eligibility depends on who claims the child as a tax dependent.
The practical takeaway: a non-custodial parent should not assume they have to pay a child’s doctor visit or prescription out of pocket. Both parents’ FSAs operate independently for the same child.
Documentation Your Plan Will Ask For
Every FSA reimbursement requires proof from an independent third party. You cannot self-certify that an expense was legitimate. A claim or debit card charge must be supported by documentation showing the date of service, a description of the service or product, and the amount charged.7Internal Revenue Service. Notice 2006-69 An Explanation of Benefits from your insurance company or an itemized receipt from the provider satisfies this. Credit card statements and canceled checks do not, because they show what you paid but not what the payment was for.
For dependent expenses, your plan administrator may also ask you to verify the relationship. Keep marriage certificates, birth certificates, adoption paperwork, or comparable records readily accessible. For qualifying relatives, hold on to evidence of your financial support: housing costs, food expenses, medical premiums you pay on their behalf. The over-50% support test is the most commonly challenged element of qualifying-relative claims, and it is the one you’ll need to be able to reconstruct if the plan or the IRS asks.