Generally no. but there is one* big exception.
There is a
special rule in the case of divorced & separated (including never married) parents.
When the non-custodial parent is claiming the child as a dependent/exemption/child
tax credit; the custodial parent is still allowed to claim the same child for
Earned Income Credit, Head of Household filing status, and day care credit.
This "splitting of the child" is not available to parents who lived
together at any time during the last 6 months of the year; then only one of you
can claim the child for any tax reasons. The tax benefits may not be split in
any other manner.
Note in particular
that the non-custodial parent can never claim the Earned Income Credit, Head of
Household filing status or the day care credit, based on that child,
even when the custodial parent has released the exemption to him.
You will have to amend* your return to do so. You'll need to wait until your previous return has been processed (you get your refund) before doing so. Be sure the other parent knows that he can not claim the Earned Income Credit, Head of Household filing status or the day care credit, so there will be no conflict.
Ref: http://www.irs.gov/publications/p17/ch03.html#en_US_2014_publink1000170897
*How to amend https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
https://ttlc.intuit.com/questions/1908543-do-i-need-to-amend-my-tax-return
*There is a 2nd, lesser known & used exception. If your child meets all the qualifying child rules, except that he provided more than half his own support, you may claim him for EIC, even though he not a dependent.
