In the case of divorced, separated, or never married parents, only one parent can claim each child as a dependent. Typically, it is the custodial parent who is legally able to claim his or her child as a dependent.
However, there are some exceptional situations in which a custodial parent will forfeit his or her right to claim the children as dependents by filing a form 8332, Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent.
In cases where custody is shared equally, the Internal Revenue Service uses what are known as "tiebreaker rules for claiming dependents" to determine which parent is eligible to claim the children as dependents.

