The IRS Form 8379, the Injured Spouse Allocation, is filed by one spouse (the injured spouse) on a jointly filed tax return when the joint overpayment was, or is expected to be, applied to a past due obligation of the other spouse.  By filling Form 8379, the injured spouse may be able to get back their share of the joint refund.

You may be an injured spouse if you file a joint tax return and all or part of your portion of the overpayment was, or is expected to be, applied to your spouse's legally enforceable past due federal tax, state income tax, child or spousal support, or a federal non-tax debt, such as a student loan.

File Form 8379 when you become aware that all or part of your share of an overpayment was, or is expected to be, applied against your spouse's legally enforceable past due obligations.  You must file Form 8379 for each year you meet this condition and want your portion of any offset refunded.