According to the IRS, "If a child is treated as the qualifying child of the noncustodial parent under the special rule for divorced or separated parents or parents who live apart described below, only the noncustodial parent can claim an exemption and the child tax credit for the child. The noncustodial parent can check this box to allow the custodial parent, or another eligible taxpayer, the EIC calculation for the child.
The special rule for divorced or separated parents or parents who live apart provides that a child will be treated as the qualifying child of his or her noncustodial parent (for purposes of claiming an exemption and the child tax credit, but not for the EIC) if all of the following apply:
- Are divorced or legally separated under a decree of divorce or separate maintenance
- Are separated under a written separation agreement, or
- Lived apart at all times during the last 6 months of the current tax year, whether or not they are or were married.
The child received over half of his or her support for the year from the parents
The child is in the custody of one or both parents for more than half of the current tax year.
Either of the following statements is true.
- The custodial parent signs Form 8332 or a substantially similar statement that he or she will not claim the child as a dependent for the year, and the noncustodial parent attached the form or statement to his or her return. If the divorce decree or separation agreement went into effect after 1984 and before 2009, the noncustodial parent may be able to attach certain pages from the decree or agreement instead of Form 8332.
- A pre-1985 decree of divorce or separate maintenance or written separation agreement that applies to 2017 provides that the noncustodial parent can claim the child as a dependent, and the noncustodial parent provides at least $600 for support of the child during the year."