Form 2120 at a glance
What it is: Form 2120, the Multiple Support Declaration, identifies each other eligible person who paid over 10% of the support of your qualifying relative whom you are claiming as a dependent.
Where and when to file: Attach to Form 1040 or 1040-SR.
Use Form 2120 to indicate that you have a signed statement from each other eligible person waiving his or her right to claim that person as a dependent.
A filled-in Form 2120 example: a daughter and her brother share her mother's support
How to fill out Form 2120, box by box
Your name and social security number
Enter the Name(s) shown on return and Your social security number.
The calendar year and your qualifying relative
Enter the calendar year and the Name of your qualifying relative.
The other eligible persons
For each eligible person, enter the Eligible person's name, Social security number and Address (number, street, apt. no., city, state, and ZIP code).
An eligible person is someone who could have claimed a person as a dependent except that he or she didn't pay over half of that person's support.
If there are more than four other eligible persons, attach a statement to your return with the required information.
The form states: I have a signed statement from each eligible person waiving his or her right to claim this person as a dependent for any tax year that began in the calendar year.
More rules for Form 2120
Don't file the signed statement with your return. You must keep it for your records and be prepared to furnish it and any other information necessary to show that you qualify to claim the person as your dependent.
If your situation is different
You did not pay over half of your qualifying relative's support
Generally, to claim a person as a qualifying relative, you must pay over half of that person's support. However, even if you didn't meet this support test, you may be able to claim him or her as a dependent if all five of the following apply.
You and one or more other eligible person(s) together paid over half of that person's support.
You paid over 10% of the support. No one alone paid over half of that person's support. The other dependency tests are met.
Each other eligible person who paid over 10% of the support agrees not to claim that person as a dependent by giving you a signed statement.
You are claiming a qualifying child
The rules for multiple support agreements apply to claiming an exemption for a qualifying relative and don't apply to claiming an exemption for a qualifying child.
You must have received a signed statement from each other eligible person
The statement must include the calendar year the waiver applies to, the name of your qualifying relative the eligible person helped to support, and the eligible person's name, address, and social security number.
Common questions about Form 2120
Who signs it?
You must have received, from each other eligible person, a signed statement waiving his or her right to claim the person as a dependent for the calendar year indicated on this form.
Sources
[1] Form 2120 (Rev. December 2025), Multiple Support Declaration, Internal Revenue Service (the Official source link on this page).